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THE SOUTHERN HEMISPHERE

Constellations

AND HOW TO FIND THEM

/•    V    %

DURING EACH MONTH OF ANY YEAR

A POPULAR GUIDE TO THE STARRY HEAVENS

A

WITH NOTES FOR SMALL TELESCOPES

16 MAPS

BY THE LATE

SIR WILLIAM PECK, F.R.A.S., F.R.S.E.

Astronomer to the City of Edinburgh; Author ofThe Observer's Atlas of the

REVISED AND ENLARGED BY

J. GALL INGLIS, F.R.S.E.

AND

R. M. GALL INGLIS

NEW AND ENLARGED EDITION.

Böinburöb:

Gall and Inglis, 12 Newington Road

AND LONDON

1947

Author’s Note in the First Edition.

This series of Maps shows the aspects of the stars and constellations from month to month, at stated times, and they are accurate for every year. Constructed on the globular projection, they give the least distortion for a whole hemisphere.

Only the principal stars of the most important constellations are inserted, to avoid confusing beginners by maps crowded with faint stars. Lines drawn through the stars show the principal features of each constellation (Condensed from original Preface).

Note to 1934 Edition.

The Introductory Chapters have been greatly extended, and an additional Map with Right Ascension and Declination lines enables the movements of the Planets to be traced. The dates and hours below the Maps now cover any hour between 5 p.m. and 5 a.m.: and a list of the constellations is given on the last page.

Note to 1947 Edition.

The Northern and Southern Hemisphere volumes of this work have been used all over the English-speaking world for more than half a century, but some remodelling is now called for, owing to the enormous increase in our knowledge of the stellar universe.

The entire text has been revised, and much of it rewritten conjointly by the present Editors, and much new matter containing the latest popular information, included. Thanks are due to Mr A. P. Norton for helpful suggestions.

Possessors of small telescopes will welcome the short notes on the various celestial objects, and the best seasons for viewing them (pp. 14-16).

Edinburgh,    J947    J. G. I.

R. G. I.

Contents.

CHAP.    PAGE

I.    ORIGIN OF THE CONSTELLATIONS 3

II.    BRIEF HISTORY OF ASTRONOMY 5

III.    GENERAL EXPLANATIONS...... IO

IV.    OBSERVING CELESTIAL OBJECTS 14

V. FINDING OBJECTS BY STAR MAPS 17

NAMES OF THE PRINCIPAL STARS ... 18 HOW TO USE THE MONTHLY MAPS 18

MAP

A.

N. POLAR CONSTELLATIONS

PAGE

18

5?

B.

EQUATORIAL „ ...

18b

?)

C.

SOUTH POLAR „ ...

18

5)

D.

OLD CONSTELLAT5N FIGURES 19

MAPS I-XIL, AND DESCRIPTIONS ... 20-31 LIST OF THE CONSTELLATIONS ...    32

PRONUNCIATION OF STAR NAMES, &C. 32

The Signs of the Zodiac, and their symbols.

Aries

T

Gemini n

Leo fi

Libra

Sagittarius $

Taurus

«

Cancer qs

Virgo TTJ

Scorpio 1T(_

Capricornus

Aquarius xc Pisces X

Made and Ptd. in Gt. Britain.

THE

Constellations and How to Find Them

“The heavens declare the glory of God ; and the firmament sheweth His handywork. When I consider Thy heavens, the work of Thy fingers ; the moon and the stars which Thou hast ordained ; what is man, that Thou art mindful of him ? And the son of man, that Thou visitest him ?—The Book of Psalms.


,OR anyone who has an interest in the starry heavens, there is no occupation

»

I more agreeable than to observe the sky on a clear night, and watch the varied positions of the constellations from season to season; noting, as the months advance, familiar stars disappearing in the west, as new groups appear above above the eastern horizon, until after the lapse of a year, the heavens will again present the same appearance.

From the very earliest ages the stars have been watched with interest and admiration, and their movements traced out and applied to various useful purposes. Their influences, too, on the fortunes and destinies of man were made the subject of ignorant and superstitious enquiry, as it was believed in those early times that the stars and planets ruled the fate of men and nations. People then thought that by a knowledge of the stars and of their movements,

they would be able to foretell events with great exactness, and imagined that Fig. i. Southern sky 4000 years ago. tpe ever varying aspect of the heavens, in their regular progression, would, if

•studied, reveal to them the secret of their future destinies. Even at the present time, when science and religion have so enlightened the world, there are those who believe in the influences of the stars, and in the power that the planets are supposed to have over famines, pestilences, droughts, wars, and earthquakes, and such catastrophies that befall mankind. It is, however, not our purpose to discuss here these points of astrology, or to debate their usefulness or otherwise, but rather to show how a knowledge of the principal stars and constellations may be •easily attained, and to point out anything that may be of interest in connection with them, in legend and in fact. So, therefore, at the outset, let us trace the growth of astronomy from its inception, briefly mentioning the pioneers, and their contribution to the advance of knowledge in the science throughout the years.

I. The Origin of The Constellations.

It was evidently for the purpose of identifying the stars that the first watchers of the sky divided the heavens into groups, or constellations, naming each group after some object to which they fancied it had ,a resemblance. As these people were probably shepherds or herdsmen, we can readily conceive how the oldest constellations were called after objects and animals with which a herdsman would be familiar in those • early times. They would picture to themselves in the different star groups, a bear, a lion, sheep, oxen, and even the herdsman and the huntsman himself. So it is, that constellation names such as Ursa Major, Leo, Aries, Taurus, Bootes, &c., are in our astronomical vocabulary to-day, names handed down through the ages.

Probably more than 4000 years have passed since the oldest constellation groups were first named by the -Chaldæans, although the Arabians, Greeks, and others, have added many constellation figures of their own, and

3

even in modern times, new names have been given to small groups of stars, but these have not always been accepted by uranographers. Evidence for the antiquity of the constellation names is proved by the ancient authors who quote them. Bootes and the Bear are mentioned by both Homer and Hesiod ; in the Bible, Tob (whose book is believed to date prior to the Mosaic period) speaks of Arcturus, Orion, and the Pleiades, also mentioned by Homer. Some schools of thought believe that in the constellations of Argo, the ship, Eridanus, the river, Aquarius, the water-carrier^ Corvus, the crow, Columba, the Dove, Ara, the altar, and Crater, the cup, the whole story of the flood is depicted, but while interesting and ingenious, it is very doubtful whether these constellations were so named with that end in view.*

Most of the constellations, as they are at present depicted, have no resemblance whatever to the objects which give rise to their names, but this may, in some instances, be accounted for. The motion of the earth’s axis round the

pole of the ecliptic will alter the positions of the stars with regard to the diurnal motion of the heavens, which affects

*

the general appearance of the constellations as compared with their appearance at present. In the case of Argo, for instance, which is at present never seen on horizontal keel—as one would suppose a ship would be seen—in early days, in the low latitudes of Chaldaea, would probably be seen just above the horizon, sailing horizontally. Again, as we do-not know for certain what actually were all the stars belonging to the old constellations, some may have been robbed of their stars, having gone to form new star groups. Some stars may have changed in brightness, and others, visible then, having diminished greatly in brightness, may be invisible to us now. Legend has it, in this connection,, that one of the Pleiades faded away, and this may be the case with other stars that were once part of a constellation visualised by ancient observers of the heavens.

That the Egyptians were concerned with accurate astronomical observation is indicated, when it is realised that: the entrance passage to the main chamber in the Great Pyramid of Cheops was so constructed that the star a Draconis


would shine down it each night, and on calculating back, astronomers find that this star was the Pole Star of these days. Thuban, as a Draconis is known, does not now shine regularly down this passage, but at the time when the Pyramids were built, the heavens did not present the same appearance as they do at the present day. We know that the Earth, besides rotating on its axis, and revolving round the Sun, reels like a mighty gyroscope, and with so slow a motion that it takes nearly 26,000 years for its axis to make one complete revolution round an imaginary line perpendicular to the plane in which the Earth moves. As the axis of the Earth moves in its circuit round this imaginary line, it points successively to different points of the heavens, and as this point, called the Celestial Pole, will not have any diurnal motion, all the stars will appear to revolve round it, or round the star that appears nearest to it.    From this circumstance that    star    will be called the Pole

Star. Thus,    4000 years ago, the Earth’s    axis    pointed in a direction

different from what it does at present, and, therefore, the constellations-at that time would appear in a different part of the heavens (fig. 2). At this axial point was the star Thuban, in the constellation of Draco, and it was therefore the Pole Star at, or around, the period when the Great Pyramid was built.

In Map A (page 18) there is a dotted circle, whose circumference comes very near to a Ursae Minoris, which is-the Pole    Star as we    know    it    to-day.    We call it Polaris, and    for well over 500 years Polaris    will    represent the Pole Star,

and some    12,000 years    from    now, a    Lyras,    or Vega, will be    the star to which the Earth’s    axis    will point, and will be-

the brightest Pole Star in the whole circuit.    •

The connection of Arabia with astronomy is evident from the names given to many of the brighter stars, and by which they are still sometimes known. For instance, there is Aldebaran, in Taurus ; Rigel, in Orion ; Dubhe, Merak, Mizar, stars in the constellation of the Great Bear, and many others. ,

The Ancients used the stars for many purposes, not least to indicate the seasons of the year. This is shown in an interesting way through the name of the constellation of Libra, the Scales. In these days, the Autumnal Equinox, or time when day and night are equal in duration, was at the season of the year when the Sun was in this constellation, and it is thought that the name was given to it to represent the balancing of the periods of light and darkness. By the stars too, the mariners knew in what direction to steer their ships by night, from their observations of the Pole Star. Precession (p. 5) has altered the position of the constellations, so that the Sun is now found in Virgo at the Autumnal Equinox.

* Columba is a modern 17th century constellation. For an account of these theories, see R. A. Proctor’s interesting book, “Myths and:. Marvels of Astronomy,” also Miss F. Rolleston’s “Mazzaroth,” and Rev. J. Gall’s “Primeval Man.”

In modern astronomy the old constellation names do not hold such important a position as they once did. Still, they form a convenient method for distinguishing the stars one from the other, though to the practical astronomer the number of a star in some important catalogue {eg, 23121) is all that is required to identify it. However, to those who only wish to distinguish the various stars, the old constellations and the individual star names are much the more convenient method of identifying them. It is doubtful if the constellation figures, which have for so long been fixed in men’s minds, and recognised by them, will ever be dismissed from astronomy, and especially from the popular aspect of the science.

89. A Brief History of Astronomy.

Perhaps the greatest of the very early astronomical discoveries was that by the Chaldaeans of the Saros Cycle of a 6585 day interval between recurring eclipses. We do not know hpw this fact was ascertained, but it is all the more remarkable when one realises that the geographical knowledge of these days was confined to a relatively small area, in the continents of Asia, Africa, and Europe, of which area Chaldaea would be the centre, and the fact that recurrent •eclipses were rarely visible twice running in the same locality.

Of the composition of the heavenly bodies our forefathers knew nothing. They were equally ignorant of the true construction of the Solar System (although one or two of the early astronomers had hit on the correct solution), and many and complicated were the theories devised to explain the movements of the Sun, Moon, and the planets, Mercury, Venus, Mars, Jupiter, and Saturn, which wandered more or less erratically among the stars. The Earth was generally believed to be fixed and immovable at the centre of the universe, and round it revolved the Sun, Moon, planets, and stars. Each of these seven planets (as the ancients considered them all) was supposed to be set in a vast invisible sphere of crystal, more or less concentric with the Earth ; each sphere had its own period, and axis of rotation, the Moon taking 27J days to circuit the star sphere; the Sun, a year; Saturn, the sluggish and most distant planet, 29^ years. Outside these revolved the “stars in their courses.” Such were the principles laid down by Eudoxus B.c. 370, (elaborating a theory of Pythagoras’ b.c. 500), and consolidated by Aristotle, B.C. 350, who was considered the authority of his time on astronomical matters.

#    t

As we shall see, this theory of the revolution of the Sun, Moon, planets, and stars, round the Earth held good until the 15th century A.D., and was maintained as irrefutable by nearly all astronomers save Aristarchus, who lived about B.C. 270. This man propounded the then heretical hypothesis that the Earth, along with the Moon and planets, revolved round the Sun, which was the centre of the universe of the fixed stars. Aristarchus had formulated the true position, but, alas, his contemporaries and successors refused to favour his theory, and so the secret of the Solar System remained hidden until Copernicus brought it to light 1800 years later. Aristarchus also endeavoured to measure the distance of the Sun from the Earth, or rather, how much further it was distant than the Moon, for apparently the distance of the latter was not yet known. His ingenious method, though perfect in theory, was not very practical, for we now know that the angles he had to measure were so small that the instruments of the time could hardly detect them at all. He believed, however, that he had succeeded, and announced that the Sun was 19 times (actually it is 390 times) more distant than the Moon. No one seems to have questioned his results, and when, some 150 years later, the distance of the Moon was measured, the Sun’s distance also became available, and on this basis was found to be 5 million miles. This value seems to have remained practically unchanged for 1700 years, until in 1618 Kepler increased it to 14 million miles ; 54 years later, Cassini found the first measurement of the Sun’s distance that was anything like true-^87 million miles. The modern value is 93 million miles.

Eratosthenes, B.C. 250, made an attempt to measure the size of the Earth, using, as the basis of his calculations, the difference in the altitude of the noonday Sun at two different places on the same meridian. His results were only approximately correct, although his method was perfectly sound.

The name of Hipparchus, B.c. 150, is one of the best known in astronomical literature, for his work and discoveries were of the greatest importance. His discovery of a new star (the first ever found) led him to compile a catalogue of stars and their positions. With the instruments at his disposal Hipparchus measured the positions of over 1000 stars, and on comparing his observations with those of earlier records, instead of discovering more new stars, as he expected, he found that many of the stars had changed their positions in the sky to some small degree. After some research, and further observations, he discovered the phenomena of Precession, the rotation of the pole of the Earth round an imaginary line perpendicular to the plane in which the Earth moves, in a period of 25,800 years. The effects of Precession on the positions of the constellations is indicated on page 4.

It is a pity that when men like Aristarchus and Hipparchus had so advanced astronomical knowledge by the

A2 8/16

brilliance of their theories and discoveries, that Ptolemy, 130 A.D., should, by his influence and his writings, bring this advance to a complete standstill for 1400 years. His Almagest set forth the current ideas regarding astronomical knowledge, to which he added his own theories. It was by his new explanation of the movements of the Sun, Moon, and planets, that Ptolemy is so well known, and his theory of deferents and epicycles tied the Solar System into as complicated a tangle as could well be devised.

His theory was based on the old Pythagorean idea of the Solar System, with the Earth as the centre of the universe, and round it revolving the Sun, Moon, and planets. To explain the irregular movements of the planets, Ptolemy devised a scheme whereby each planet moved in a circular orbit called an epicycle, the centre of which, in its turn, moved in a circular orbit called a deferent, round the Earth. Finding that this theory did not entirely explain the planetary movements, he introduced a new complication, by giving the orbits described by the deferents, a centre at some distance from the Earth. This, of course, gave the epicycle a new orbit, and the system was even more involved than before. The immense prestige of this astronomer is indicated by the fact than from 130-1500 A.ix no one    contradicted his theories, and even when the truth was known, it was slow to be favoured.

It    was Copernicus (1473-1543) who opened up a new era in astronomy, by setting forth the    correct    theory of the

structure of the Solar System. Round about the year 1525 he came to the conclusion that the Sun was at the centre of the universe, and that the planets, in order of distance, Mercury, Venus, Earth (round which revolved the Moon), Mars, Jupiter, and Saturn, revolved round him. Not until the year of Copernicus’ death was this epoch-making fact publicly revealed in his book “ De Revolutionibus Orbium Celestinm.”

The next name on the list of notable astronomers is that of Tycho Brahe (1546-1601), who, after discovering a brilliant new star in Cassiopeia in 1572, devoted his life to a systematic series of observations on the movements and positions of the Sun Moon, and Planets, which proved of immense value to his successors. He also compiled a star catalogue.

From a careful study of these observations, one of Tycho’s pupils, Johann Kepler (1571-1630) became the first to discover definite laws that govern the movements of the heavenly bodies. His three laws relating to the orbits of planets are of the highest importance.

1.    The orbit of a planet is elliptical, the Sun being at one of the foci of the ellipse.

2.    The line joining a planet and the Sun sweeps out equal areas in equal intervals of time.

3.    The squares of the times of a planet’s revolution round the Sun are proportional to the    cubes of    its    distance

from the Sun.

With the invention of the telescope by a Dutch optician in the early years of the 17th century, a new phase in astronomy opened. It may be called the Observational era. Galileo Galilei (1564-1642), usually known by his Christian name nowadays, applied the new instrument to solve the mystery of the nature of the heavenly bodies,, hitherto unrevealed. Pie was the first to see the craters of the Moon, the phases of Venus, the four main satellites of Jupiter, and the rings of Saturn, as well as the wonders of the starry heavens in the Milky Way, and the cluster of the Pleiades. His observations on the nature of sun-spots roused bitter resentment among the ecclesiastical leaders of his day, and these gentlemen, being stout adherers to the Aristotelian-Ptolemaic theory of the Solar System, took the opportunity to persecute Galileo for his theories regarding sun-spots, and for his belief in the Copernican theory,, which he had proved beyond argument by his discovery and observations of the satellites of Jupiter and their movements. He was forced to recant before the threatenings of the Inquisition, but in his own mind he was quite certain that he had stated the truth.

Edmund Halley (1656-1742) made a notable contribution to astronomy by his observations of comets, and noted the similarity of the paths of several observed previously, from a study of their positions as set down in the available records. He concluded that these objects were connected with the Solar System, moving round the Sun in very eccentric ellipses, and he correctly forecast the return in 1758 of the brilliant comet he had observed in 1682* and which now bears his name. It returned in 1835 and 1910 and is next due about 1985.

The first accurate map of the Moon was made by Tobias Mayer, but was not published till 1775, several years after his death. His observations of the positions of the craters and “seas” laid the foundation of Lunar study, which has been so perfected that to-day the features on the Moon’s surface are even better known than some regions on our own Earth.

With Sir Isaac Newton (1643-1727) came the beginning of the mathematical era in astronomy, and no one needs to be reminded of the importance of his laws on motion and definition of gravitation. “ Every particle of matter in the universe attracts every other particle with a force proportional to their mass, and inversely proportional to the square of their distances.” Here was a fact, which, if applied to the Celestial sphere, accounted for many of

the hitherto unexplained irregularities in the movements of the planets. The tremendous realisation now dawned that this force of gravity extended far beyond the confines of the Earth, and could be traced throughout the bounds of the Solar System, and probably even further, and affected each of its members severally.

In the beginning of the 18th century, astronomers began to formulate theories regarding the origin of the Solar System. Chief of these theories was that of Laplace (1749-1827), whose “ Nebular Hypothesis” formed the basis of belief in this direction for more than a century. Noticing that all the then known planets revolved round the Sun in the same direction, and that the satellites likewise moved round their primaries, and that both planets and satellites rotated on their respective axes in still the same direction, he concluded that there must be some connection betv/een them and their common origin. He supposed that the entire Solar System was at one time a nebula similar to the spiral objects that telescopes were soon to reveal for the first time, their very form indicating rotation. Endow this nebula with rotation, and suppose that from time to time parts break off from its circumference and form separate nebulae, which in turn detach smaller nebulae. Let all these gradually cool and solidify, and you have the existence and direction of motion of the planets and satellites accounted for, all revolving round the present Sun, the core of the once vast nebula. Such was Laplace’s idea of the origin of the Solar System, and it has only comparatively recently been discarded in favour of the “ Tidal    This suggests that the Sun and another star,

at some remote time, passed close to one another, and that the tremendous force of attraction drew out masses from the Sun, which formed the planets, the respective satellites being drawn out of their primaries by the attraction of the Sun. Even this theory does not account for all the motions of the planets, and the true solution is still being sought for.

By far the most famous of the 18th century astronomers was William Herschel (1738-1822), who, by his researches and observations, enlightened so many branches of astronomy. He constructed many telescopes and mirrors, increasing the power and capabilities of each new one, and set himself the enormous task of making a systematic series of observations of the whole heavens. His labours were rewarded in 1781 by the discovery of a new planet beyond the orbit of Saturn, which was subsequently named Uranus.

The observation and cataloguing of nebulae and star clusters was another of Herschel’s labours. He made several catalogues of these objects, and classified them into their respective forms, and after many years of careful study set forth his theory that stars and star clusters were the final stage in the process of evolution from a nebula. In his studies of double stars Herschel discovered a new class of object “ binary stars? With his customary care he had made a catalogue of double stars, recording the positions and separation of the components, and many years later found that the positions in some of the stars had altered, and that the components were revolving round one another.

Herschel also made investigations into the proper motions of the stars, which were now becoming evident from a comparison of their present positions with those recorded in the ancient catalogues. He noted that, in general, their motions corresponded with the celestial phenomenon exhibited when a person walks down a long avenue of trees. He appears to be on the bisector of an isosceles triangle, looking down to the apex, and in his walk down the avenue, finds the narrowing lane he viewed at first, opening up as he advances. Herschel concluded from his observations that the Sun and planets were moving* toward a point in the heavens which he called the Solar Apex, and which was situated in the constellation Hercules.

The problem of bridging the gulf that separated the Earth from the stars, however, still remained unsolved ; all Herschel could say with certainty, was that their distances could not be less than 19 billion miles, otherwise his instruments would certainly have revealed them, also that their light must take at least three years to reach us. Foiled in direct measurement, it occurred to him that he might get the minimum possible dimensions of the universe indirectly, by assuming, as was fairly reasonable, that, on the average, the stars were of equal intrinsic brightness. In that case, the brightness of the stars of the same magnitude, would be an index to their distance, so that the millions of very very faint stars, only visible in his great telescopes, must, on the average, by optical laws, be a thousand times further away than Vega, which, as the brightest star in the Northern Hemisphere, was presumably one of the nearest. As the light from the latter was known to take at least three years to reach us, that from faint stars must take at least 3000 years, and this must be the minimum size of the Universe.

It was not until 1838 that Bessel measured the first star distance, that of the star 61 Cvgni, thus bridging the gulf that Herschel could not cross. Curiously enough, the nearest star that we know to-day, Proxima Centauri, is not much over Herschel’s minimum distance, it being distant 4% light years ; but Vega is eleven times more distant.

In mentioning the discoveries of William Herschel, reference to the work of his sister Caroline and his son John, cannot be overlooked. Caroline Herschel not only acted as her brother’s housekeeper, but also as his observatory

* The Sun is travelling through space 12 miles every second, 720 miles every minute, 43,000 miles every hour, and a million miles every day. So far are the depths of space, that even at this speed, after travelling a billion miles, he would not have traversed i/25th of the distance which separates us from the nearest fixed star, which would take 65,000 years to reach.

assistant, and often sat up with him all night at his telescope, taking down observations at his dictation. She herself was a keen observer, discovering several comets.

John Herschel (1792-1871) both supplemented and extended his father’s work, first of all remeasuring a large number of the double stars observed by him, and thereby detecting new binaries from a comparison of his observations with those in his father’s catalogues. He pioneered the skies of the Southern Hemisphere during a four years’ stay at the Cape of Good Hope, and new catalogues of double stars and nebulae were the result of his observations.

It has been recounted above how Herschel discovered the first new member of the Solar System, Uranus. The 19th century opened with the discovery by Piazzi of Geres, the first Minor Planet. Up till 1830 four others were discovered, but thereafter new ones regularly came to light, and to-day, over a thousand are known.

Observations of the planet Uranus showed that discrepancies arose in its predicted positions, from those it actually occupied, so after some study of the matter, astronomers began to suspect the existance of a hitherto undiscovered planet that was responsible for the irregularities in Uranus’ motion. Unknown to each other, an Englishman, Adams, and a Frenchman, Leverrier, had set themselves the task of calculating an orbit for the undiscovered object, and within a few months of each other arrived at a satisfactory conclusion as to its position in the sky. Telescopic search for it was made in the region of the sky indicated, and so, in 1846, Neptune was observed and added to the Solar System. It has now been agreed that the honour of the discovery be shared between both Leverrier and Adams, for it was only an unfortunate series of mishaps that prevented the young Englishman’s figures being put to the test sooner.

Even Neptune’s orbit was later found to be disturbed by influences outside that of Uranus, but it was not until 1930, that Pluto, the outermost known planet, was discovered by the aid of photography. Sections of the heavens are photographed at intervals of a few days, the plates carefully compared, and if any object is found to have altered its position, it is carefully and regularly watched, its successive positions tabulated, until its nature is ascertained. Thus Pluto was found. On plates which have been given long exposure, minute streaks of light are sometimes found, indicating the presence of an object within the bounds of the Solar System. Minor Planets are traced in this way. The camera has opened up a new sphere in astronomical research, for, by its aid, objects far beyond the power of any telescope can be brought to view. By taking exposures of many hours’ duration, nebulae have been discovered that are so distant that their light, travelling at the speed of 186,000 miles every second, takes hundreds of millions of years to reach us.

As early as 1665 Newton had demonstrated how light could be resolved into its primary colours by passing it through a prism, and he had obtained the spectrum of light on a screen, showing the seven-coloured band now so familiar to us. In 1814, Joseph Fraunhofer, examining the Sun’s spectrum by aid of the newly discovered spectroscope, observed a number of dark lines running across it perpendicularly, all along the band. He made a careful sketch of these, noting their respective positions and groupings. It was not until some thirty years later that Kirchoff proved, after various experiments, that these lines indicated the presence of certain metals in the Sun. The spectroscope was applied to the light coming from other heavenly bodies, with the result that we now know the composition of not only the Sun, but also of the stars themselves.

In 1842, Doppler announced that the spectrum of a moving body showed differences from that of the same body when stationary; the positions of the lines differing to some small degree. This important fact was taken up by Sir William Huggins in 1868, who put it to use in detecting the motions of the stars. From an examination of the exceedingly minute displacement of lines in their spectra, it could be ascertained whether a star was moving toward or away from the Earth.* Another remarkable use to which spectroscopy is put, is in the discovery of Spectroscopic Binary Stars. In photographing the spectrum of certain stars it was seen that at times one or more of the lines in the band appeared double. Putting Doppler’s theory into effect, it was surmised that the stars, only appearing single in the telescope, were actually composed of two stars revolving round one another. Applying this test to the variable star Algol, it was found that as there was a shift in the lines of this star’s spectrum at irregular intervals, corresponding to its variability, the existence of a dark eclipsing companion was proved, and the cause of variability of Algol explained. Stellar Photometry in the 20th century has led to the ascertaining of the temperature and diameter of the stars, but it is quite outside the popular nature of this book to go into details regarding these methods. Suffice it to say that some stars are similar to the Sun in composition, size, and temperature t; others, like Sirius, hotter still; others, like

* Many spiral nebulae are receding from us 250 miles every second, or 20 million miles per day !

+ The Sun belongs to an inferior order of suns, and it is known that he has already passed his prime. Sirius belongs to a higher order, exceeding the Sun twice in diameter, and 26 times in brightness. Betelgeuse is over 250 times the diameter of the Sun, while Canopus (not seen in Britain or Southern Europe, but close to the horizon in the United States) is believed to be 80,000 times more luminous than the Sun.

9

S in Orion, great globes glowing with a temperature of 35,000 degrees Fahrenheit, three times that of the Sun, while others, like Betelgeux, are cooler, being in an earlier stage of development. It reveals, too, that the seemingly ‘ fixed ’ stars are rushing through space with tremendous velocities; measures how fast they are approaching us or receding from us; tells of what may be other Universes far away in the depths of space, which ate revolving on a axis in periods of tens of thousands ot years, or flymg away from us at the rate of thirty million miles a day. It can even give an idea of the distance of many stars hopelessly beyond the possibility of direct measurement. It has shown, too, that many stars seen as a single point of light in the most powerful telescopes, are in reality composed of two stars revolving round one another, and even gives us the period of their revolution, from which some idea of their distance can be formed, and reveals that many of the faint luminous patches called ‘nebulae,’ previously believed to be clustering stars, too faint to be seen individually, are really masses of glowing gas.

Of course, all these marvellous achievements were not attained at once, and are not due to astronomers alone; the mathematician, physicist, and chemist on the one hand, and the optician and engineer on the other, have shared in making them possible, each in his own line ceaselessly striving for further advances. Also the mere lapse of time has put us in possession of facts as to the very slow changes in the position of the stars on the star sphere, suspected but not known definitely by our fathers, who sowed much of the rich harvest we now reap.

■ ‘Cepneid ’ Variable Stars. Study of this type of variable star (p. 16) has revealed that those with the same variation-period have the same absolute brightness. Thus, knowing their period, and how bright they appear to us, a fairly reliable estimate of their distances can be made, to a million light-years, or more.

Giant and Dwarf Stars. Spectroscopic study of the stars, and of their absolute brightness (p. n), shows that they are divided into two classes, known as ‘Giants’ and ‘Dwarfs,’ respectively—the Giants having exceedingly small density but enormous diameter,* and great luminosity per square mile (or ‘absolute magnitude’); the ‘Dwarfs,’ moderate density and diameter, comparable with those of the Sun, and small absolute magnitudes, fainter than i'o. At one stage, however, the two types pass insensibly into one another, so that the names, in the literal sense, only apply towards the extremes. And as the spectra of the stars give a fair idea of their temperatures, and seven types of spectra seem to form a distinct sequence—known as Types O, B, A, F, G, K, M, and progressing in that order—it is believed that these types indicate the life-history of a star, though that history must occupy untold ages. The ‘M’ stars are red, and ‘late’ (low-temperature) stars; B, A, ‘early’ or high-temperature stars.

Life-history of a Star. In the course of their lives, stars apparently pass twice through the same colour and temperature stages, each beginning its career as a dark gaseous nebula, the matter of which has gravitated together. Its particles gradually draw closer together under the action of gravity, evolving heat, some of which is radiated and lost, while the rest, by gas law, raises the temperature of the shrinking nebulous mass. After many ages it gets hot enough to be visible, and appears as a red ‘Giant’ ‘M’ star like Betelgeux, with a temperature of some 5000° Fahr.—about that of the electric arc—and a diameter of very many million miles, yet with a density exceedingly small per cube mile, no more perhaps, as in Antares,than i/30ooth of that of our atmosphere ! In due time, still further contraction raises the temperature to that of Arcturus (Type K), so that it shines with a yellowish light; still later it reaches successively the temperature of the Sun (io,ooo° F.), shining like Capella (Type G); of Canopus (Type F); and finally of a Andromedse (Type A), when it is very white, and its temperature is some 20,000° Fahr. Hereabouts the average star probably reaches its prime, and its limit as a ‘Giant;’ if, however, its mass is greater than the Sun’s—which is somewhere about the average—it seems to go a stage further, until it glows bluish white as a ‘B’ star of some 35,000° Fahr., or more, like Rigel and 8 of Orion. ‘O’ stars are even hotter.

All this time, the ‘luminosity’ (total amount of the star’s light) has remained fairly constant, for the increase in the brightness of each square mile has been compensated by the ever-diminishing area of the star’s surface. But now there is a change; ages of contraction and radiation have raised the density of the star to something like 1 /7th that of water; its closely-packed atoms are no longer in condition to obey ordinary gas law, and it loses heat more rapidly by radiation than it evolves by shrinking, and begins to cool, thereby passing into the rank of the Dwarfs, though, at this stage, there is practically no difference between Dwarf and Giant. Much more rapidly than it grew brighter, it cools and fades, and gets denser and denser, passing back again through the same temperature and colour stages as during its rise, in the reverse order, as exemplified by the Dwarf stars Sirius, the Sun, and Proxima Centauri—the last star (p. 30) apparently on the verge of extinction. Then it becomes a dark star, and its ultimate destiny is beyond our ken. Yet, though this life-history may be fairly correct in a general way, the details may after all be different, for it has recently become certain that the stars must be literally burning away their mass—decreasing both in weight and in absolute brightness, which last is always proportionate to the mass.

Such is the story read from the book of the stars by astronomers, but they warn us that some of the signs may not have been deciphered aright, and that when they pass on to pages as yet unread, these conclusions may have to be modified or altered, as has happened so often with their predecessors’ conclusions in the past.

* The diameter of Antares is some 400 million miles ; the Sun’s is 864,000 miles: his density, 1^ times that of water.

III. General Explanations.

IO


The Fixed Stars. When we go out on a clear evening and examine the heavens, we seem to be at the centre of a vast hemispherical dome, on the surface of which the stars sparkle like tiny fairy lamps. Night after night the seeming dome circles in silence, bearing with it the stars, each of which describes its own circle, great or small; even a centenarian can trace no difference in their relative positions from what he saw as a boy, and to all appearance they are immoveably fixed to the inside of the seeming dome: the only exceptions are a few planets—literally, “wanderers”—which move in apparently erratic paths round the celestial vault. Two points, diametrically opposite on the dome (only one of which is ever seen, except by those on the equator), do not share in the rotational movement, being the poles, or pivots as it were, on which the dome turns.

Thus we speak of the “fixed” stars, although we now know that they are all sweeping through space with tremendous velocities, and that their seeming fixity is merely the result of their vast distance, which so reduces the scale of even a very great movement that centuries may be needed to detect it.

The Star Sphere. This seeming dome of the heavens is spoken of as “ The Star Sphere.” We can only see half of it at one time, and, of course, it has no real existence; but for practical use in star-finding it is very convenient to assume that it is real, and that the stars are fixed on it—as even the learned believed, not so long ago. At the Earth’s equator, all the star sphere is observable; elsewhere, some portion of it, large or small, is never seen.

Culmination. A celestial body “ culminates ” when it reaches its highest point above the horizon of the observer, and at that instant it is always on the “meridian” of the observer, i.e., the line in the sky, drawn:—

Northern Hemisphere. From the North Celestial Pole, to the point on the observer’s horizon, exactly South of him.

Southern Hemisphere. „    „ South „    „    „    „    „    „    „    „ North „

In the Northern Hemisphere, stars are therefore said to ‘south’ (S. Hemisphere, ‘north’) when on the meridian; but ‘culminate’ conveniently serves for either hemisphere, and for stars near the Pole which never ‘south’* (or ‘north’) to the observer. ‘On the meridian,’and ‘ transits,’have the same meaning as ‘culminates.’ The Sun always culminates at local noon; the stars only culminate once a year at the same hour; the planets are irregular.

Daily Movement of the Stars. The star sphere appears to us to revolve from east to west, in consequence of the daily rotation of the Earth on its axis in the opposite direction, giving rise to the rising and setting of the Sun and stars. A revolution is completed every 23 hours 56 minutes 4 seconds, and as this is nearly four minutes shorter than the 24-hour solar day, it is evident that to see the stars in exactly the same position, we must go out four minutes earlier each night, until at last we have to go out so soon that they are lost in daylight. Or,, if we go out at the same hour each night, the stars which were culminating the first night at that hour, will, on the second night, have passed four minutes westward; on the third night, eight minutes, and so on, till, thirty days later, they will be two hours (= 30 x 4 minutes) past culmination, and sooner or later will have set at that hour.

The stars and planets therefore, that can be seen from a given place (p. 17), are not always visible, although for part, at least, of every day they are above the horizon, owing to the Earth’s rotation; at a certain period they set so soon after the Sun that they cannot be seen for his light, and remain invisible in his rays for a longer or shorter period, until sufficient time has elapsed for them to travel past the Sun, and rise before him in the east. But all those ‘ circumpolar stars’ which are a less distance in degrees from the seen celestial Pole than the observer is from the terrestrial Pole nearest him, never set, and are always seen after sunset; while those in the corresponding region round the unseen celestial pole never rise at all. After exactly one year, the stars all return to the same position at the same hour, as the Earth has completed her revolution round the Sun.

Daily Movement of the Sun. Could we simultaneously observe both the Sun and the stars behind him, we should find that, as the result of the Earth’s orbital motion round the Sun, he is changing his position among them on the star sphere day by day, apparently moving eastward about one degree (twice his own angular diameter) each day. At the end of a year he has completed a circuit of the star sphere, having travelled exactly 360°. As the result of this daily motion, the Sun appears to be always moving eastward to meet the stars seen in the evening, so that in due course they become lost in his rays ; on the other hand, he appears to be always retiring from the stars seen in the early morning, so that after a while they are quite free from his effulgence.

Daily Movement of the Planets among the Stars. On the whole this is eastwards, but the combined effect of the Earth’s motion and its own, may make a planet stationary, or move ‘retrograde’ (westwards), for a time.

Average daily change:—Mercury 4°, Venus i|°, Mars |°f, Jupiter -08°, Saturn '03°, Uranus 'oi°, Neptune -006°. ,, yearly ,,    ...    ...    ,, 191J ,    ,,    3°? ,    ,,    12^ ,    ,, 4J ,    ,,    2^ .

The Ecliptic, and Zodiac. As the path of the Sun among the stars—the Ecliptic—remains the same every year, its position in the sky at any time can be found from Maps I to XII. It is of great importance to the amateur observer, for it is not only the path of the Sun, but also the average path of the Moon and planets, and indicates the middle of the narrow band in the sky—extending 8° on each side of the Ecliptic—within which Sun, Moon, and planets are always found. The ancients named this region ‘The Zodiac,’ meaning ‘Path of the Animals.’

* In the literal sense.    + = the angular diameter of the Full Moon.

The Signs of the Zodiac. These are named after the twelve constellations traversed by the Zodiac, but now do not coincide with the constellations of the same name. Each ‘sign’ includes i/i2th (30°) of the Ecliptic, starting from the First Point of Aries: the old rhyme gives their sequence (names and symbols, see p. 2):—

The Ram, the Bull, the Heavenly Twins ; And next the Crab the Lion shines:

The Virgin, and the Scales :


The Scorpion, Archer, and Sea-goat: The Man that holds the Waterpot: And Fish with glittering Tails.


Star Magnitudes. As every one knows, some stars shine more brilliantly than others. Astronomers divide all the lucid stars (i.e., those visible to the naked eye) into divisions, called ‘magnitudes/ the brightness decreasing as the magnitude figures increase. The brightest stars are called ‘first magnitude’; those not quite so bright, ‘second magnitude/ and so on till the sixth magnitude stars, the faintest visible to the naked eye. Stars still fainter, from the 7th to the 21st magnitude or more, are called ‘telescopic stars; the faintest are only visible in giant telescopes (to about mag. 18), or on photographs, which record faint stars that the eye cannot see.

There are various kinds of magnitude:—(1)    Visual, (2) , approximately identical; (3) Photographic

(in ordinary photographs) often quite different from the visual magnitude as seen by the eye : blue stars appear too bright, and red stars far too faint: well-known star groups may thus be difficult to identify. (4) Absolute magnitude.* For accurate comparison, astronomers measure in iooths of a magnitude, thus a star of magnitude 3*20 is brighter than one 3*21: each whole magnitude is 2| times brighter than the one below it. For stars brighter than i’oo, the increasing-brightness figures go on o-99, o’98, . . . till o’oo, as 11 stars range from mag. C92 (    )

to o-i4 (Vega). After o-oo, the figures are minus, and increase with brightness: Canopus is - o'86, Sirius, — 1*58.

Relative Brightness of Stars. Fig. 3 shows all the stars visible to the naked eye (the first six magnitudes) in the N. and S. Hemispheres — some 6000-7000; rather more than half are in the Southern Hemisphere. The Table below shows the relative amount of light that reaches the Earth from stars of these first six magnitudes, magnitude roo being taken as 100—on this ‘Harvard’ scale there is no star exactly 100: the nearest are a Crucis and Aldebaran. A dozen ‘first magnitude’ stars, however, have a brighter light-ratio than 100. On the same scale,. Saturn averages 590; Mars, 2000; Jupiter, 2000. At maximum, Mercury, 1300, Venus, 13,000, Moon, 19 millions.


• : •• ■■ : - ■*


Fig- 3

Southern

Hemisphere


. .

■r.'    y


Star

Mac- Ratio

Star

Mac-

Ratio

Star

Mag.

Ratio

Star

Mag. Ratio

Star

Mag. Ratio

Mag. R

Sirius

-1-58

1070

Arcturus

0-24

200

Affair ...

0-89

in

Spica ...

1-21

82

Regulus

1-34

73

2-00

Canopus

-0-86

550

Rigel ...

0-34

184

Betelgeux

0-92

108

Pollux

1-21

82

ß Crucis

1-50

63

3-00

a Centauri 0*06

237

Procyon

0-48

161

1st Mag.

1-00

100

Antares

1-22

82

Castor

1-58

59

4-00

Vega

0-14

220

Achernar

0-60

145

a Crucis

1-05

96

Fomalhaut 1*29

77

7 Crucis

1-60

58

5-00

Capella

021

207

ß Centauri 0 86

114

Aldebaran 1'06

95

Arided ...

1-33

74

eCan.Mj.

1 63

56

6-00

40

16

6

24

For telescopic magnitudes, taking a 1st magnitude star as 1, instead of 100, and Mag. 6 as i/iooth instead of 1, Mag. 11 is i/xo,oooth; Mag. 16, 1/millionth; and Mag. 21,1/100 millionth, of the brightness of magnitude 1.

Star Names. The ancients gave individual names to the most important stars (see p. 18), the only method of recognising them till 1603 a.d., when Johann Bayer of Augsburg introduced the system of distinguishing the stars that has ever since been employed by astronomers. In this system, the names of the old" constellations are still kept, but each star is designated by the small letters of the Greek alphabet, usually calling the brightest star in a constellation after the first Greek letter; the second brightest by the second letter, &c.:—thus a (Alpha) Lyræ is the brightest star in the constellation of Lyra ; (3 (Beta) the second brightest, and so on till all the Greek letters are exhausted ; sometimes, however, these rules have not been adhered to.

When the number of stars in a constellation exceeds the number of Greek letters, then small (sometimes capital) Roman letters are used, a, b, c, d, . . . . following &> (Omega), the last Greek letter. The capital letters of the Roman alphabet from R to Z are now used exclusively to indicate the variable stars of the constellation.

* Absolute Magnitude. Some very faint stars are quite near us; some of the brightest ones are very far away. If their distances are known, a simple calculation tells what magnitude each would appear to us if they all shone at a standard distance of 32£ light-years away ; the magnitude so found is called a star s ‘ absolute magnitude’ : it enables the real relative brightnesses of stars to be compared. The Sun's

absolute magnitude is 4 9.

Star-Catalogue Numbers. Many faint stars have neither Greek nor Roman letters, and the only means of identifying them is to give their number in a certain star catalogue. The numbers of the catalogue prepared by the first Astronomer Royal, Flamsteed, are m universal use for stars having no Greek or Roman 'letter thus7

61 Cygm. \\ here there is neither letter nor Flamsteed number, the star is identified by giving the name of some other star catalogue containing it, and its number in that catalogue, thus, “ Wolf 359.”

Tlae Mllky Wa-y- 9" any dark and clear “Sht> when there is no Moon, a broad faint band of cloudv lg will be seen stretching right across the heavens from one side to the other, at one season arching high overhead, at another, lying near the horizon. This is the Milky Way or Galaxy, which completely circles the star sphere, passing within twenty or thirty degrees of the celestial poles : its varying position in the sky is shown on ne ’naps. It is all visible to most observers in the Southern Hemisphere, except the northern edge in Cassiopeia and Cepheus, but Northern observers (unless south of latitude 30-35”) only see the part passing through, or near Scorpiusy* Sagittarius, Aqu.la, Cyprus, Cepheus, Cassiopeia, Perseus, Auriga, Gemini, and Cams Major. From ams Major to Amiga, it is regular in outline but exceedingly faint; while, on the other hand, the portion which traverses Scorpius, Sagittarius, Aquila, and Cygnus, though more conspicuous, is very irregular in appearance

That portion of the Milky Way which is invisible in Britain and most of the United States—some 50-60° long near the Southern I ole-passes through Argo, Crux, Ara, and Centaurus. In this region of the heavens, it shin?s more conspicuously than m the Northern Hemisphere, but in Argo, the brighter portion of the stream is completely < mded by a dark and curiously-shaped opening. Near the Cross it is very bright, though some of the luminous patches m the constellation of Sagittarius, probably near the centre of our System, may be even more brilliant

It is now believed that the Milky Way is really an unbroken circle, the rifts and gaps we see being the result o opaque non luminous clouds of fine dust, which intervene between us and the Milky Way

The Nature of the Milky Way. When examined with a powerful telescope the Milky Way .    * p


in the brightest parts of its course, is truly a magnificent sight-(Fig. 4). Even with so small an instrumentTan opera glass, the vast number of stars that are rendered visible, is well calculated to impress the least thoughtful mind with a sense of the omnipotent power, and the infinite wisdom of the Creator, who brought so many suns into existence (for each of the many million stars seen in the Milky Way is a sun like our own), so we do not wonder that, when the celebrated Schroeter was observing a part of the galaxy near Arided (a) in Cygnus, with a 19-inch reflecting telescope, he was so impressed with the infinite grandeur of the scene that it drew from him the natural exclamation, “ What Omnipotence ! ”

Ancient Ideas of the Milky Way. But ages before the telescope was even thought of, the Milky Way had attracted considerable attention; in fact, some ancient astronomers who had watched this luminous band as it stretched across the heavens, had even arrived at the conclusion that its milky whiteness would, in all probability, be produced by the combined

lustre of myriads of stais, individually indistinguishable at such vast distances Fig. 4. Small part of the Milky Way away; thus Ovid says that £ It is a road whose ground-work is of stars,’and    as seen with a Telescope.

“A broad and ample road, whose dust is gold, And pavement stars, as stars to thee appear


Manilius, another Latin poet of the ame era, uses similar language. But its true nature only became known with certainty when Galileo first turned the telescope to the Milky Way. That instrument revealed to him the glorious assemblage of stars of all orders of brightness; from those which appeared to him as bright as the leading stars in the heavens, down to the smallest visible points of light, only momentarily glimpsed, as they glittered like a sprinkling of diamond dust against the background of the sky. Milton thus describes the Galaxy

Seen in the Galaxy, that Milky Way,    [ stars.”

Which nightly as a circling zone thou scest, Powdered with

„    . Unresolved Stars. But though Galileo’s telescope revealed enormous numbers of stars never seen before

individually, theie were parts of the Galaxy that it failed to penetrate—that same misty light, which for ages had engaged the attention oi astronomers, still remaining in the background. With every increase of telescopic power more stars were seen, and greater depths were reached, but only to find, as Galileo had found, that still some parts would require a more powerful instrument to separate the individual stars, that, being so closely crowded together and so distant, caused this cloudy light. Herschel’s powerful 4-foot reflector, then Lord Rosse’s gigantic telescope, 6 feet in diameter, then the still greater Mount Wilson telescope of 1918, in America, 8^- feet in diameter and more than twice as powerful, far though they penetrated into infinite space, could not resolve some of the luminous patches scattered throughout the Milky Way. Nevertheless it has long been considered as demonstrated, that the milky light is caused by myriads of faint stars, too close to be seen separately.

* Now used instead of ‘Scorpio.*

The Extent of the Milky Way. If we could see all the Milky Way at one time, it would appear to us as an irregular, tolerably narrow band round the star sphere, slit horizontally towards one end; but seen from the outside it will probably appear as a spiral nebula, like that in Andromeda (p. 31). At one time there was reason to believe that the Sun was situated centrally in the Milky Way, but the Galaxy is now thought to be a lens-shaped aggregation of stars—longest diameter, some 300,000 light years; the Sun appears to be situated a little north of its equator, and some 60,000 light years to one side of its centre, near the middle of what is known as ‘The Local Cluster,’ i.e., a bun-shaped region of stars which are more closely packed together than those lying between us and the Milky Way, and near the Sun as compared with the other stars. It is not yet known whether the Milky Way band is merely an optical effect resulting from the stars extending to a greater distance, and being more closely crowded, in that direction, or whether there is something of the nature of an inner boundary to its concentration— indeed all the above hypotheses are admittedly only tentative, meanwhile.

Shooting' Stars. Sometimes on a clear evening one is startled by a bright train of light suddenly coming into view, and gliding across the sky with great rapidity, and then disappearing. This is a meteor or shooting star. They may be seen any clear night, and on certain dates—notably November 13 and 27, August 10, and April 20—they are seen in great numbers. These falling stars have from time immemorial attracted attention, and many theories have been advanced as to their real nature. At first it was supposed that they were decomposed fluids—such as the gases emanating from marshes—floating in the higher strata of the atmosphere, which, after reaching a considerable height, became ignited, and thus appeared as shooting stars. Then it was supposed that they were the same as aerolites, or meteoric stones, perhaps ejected ages ago from volcanoes in the Moon—or even-in the Earth, when volcanic activities were more powerful than now.

Meteor Showers. Within the last century or so, however, it has been found that when the tracks of shooting stars, seen on the above-mentioned and other dates, are traced backwards, nearly all meet in the same point in-the heavens—    i.e.,year after year, the meteors in each of these displays all appear to radiate from their own definite


point on the star sphere, which is known as the ‘radiant ’ of that shower. Fig. 5 shows the position among the stars of the Radiant of the meteors seen in the early hours of November 13-15. It wil-l be noticed that these meteors appear to radiate from a point in the

‘sickle’ of Leo, on which account this shower is named Th Leonids. Similarly, those seen about August 10 and November 27 are called Perseids and Andromedids, respectively: those on April 20, Lyrids, as the radiant is near Vega in Lyra.

The Nature of Meteors. As the radiant of each shower is in the same place, year after year, it became obvious that meteors must be in the nature of swarms of minute planetary bodies, revolving round the Sun in very eccentric orbits. The Earth is sometimes quite near their orbit—may even pass through it—and, at such a time, the Earth’s attraction draws many of them towards her, and the nearer they get, the greater becomes the velocity. By the time they reach the outside of our atmosphere, their speed is so great that when they plunge into it an immense heat is generated—caused by the friction of the air—which is generally sufficient to consume them long before they can get near the Earth’s surface.

The Size of Meteors. As meteors generally appear at a height of seventy to fifty miles (a few as high as 150 miles), and disappear from forty to twenty miles above the surface, one would suppose that they must needs be of considerable size to appear so bright at such a distance. But, strange as it may seem, all the evidence agrees that the average meteor we see weighs no more than one grain; a very bright one, three or four grains.

Aerolites. If meteoric stones are big enough, they will not be wholly burnt up, but part of them will arrive at the Earth’s surface; these are known as aerolites. Some are metallic iron; others stone, similar to materials we should expect to find if they had once been part of the Earth or Moon.

Many of them—some weighing tons—have been found in various parts of the Earth, and some have been picked up shortly after they had fallen, while yet hot. In our museums, meteoric stones can be seen which probably travelled through space for untold millions of years before they came within the attractive influence of our Earth, and were thus brought down to us.

Meteors and Comets. While it is likely enough that some meteors may have a terrestrial or lunar volcanic origin it is now known that a number of meteor orbits are identical with those of known comets. Shooting stars are thus captures by the Earth from dust-swarms of meteoric stone and iron, following in the train of existing—or long-dissipated—comets revolving round the Sun.

These comets, with their trains of meteors—perhaps at one time ejected from some of the stars—travelled through space, till, coming too near the Solar System, they were captured, and thenceforth revolved round the Sun.

IV. Notes on Observing Celestial Objects.

■*4


[It is beyond the scope of this book to deal descriptively with the various celestial objects, as details of these can be obtained from any astronomical textbook ; but the following notes on the most suitable times for observing them will be helpful to those who possess a small telescope, or even a good opera glass. They are condensed from much fuller paragraphs in “Norton’s Star Atlas and Telescopic Handbook,” which is recommended to those who wish to study observational astronomy in greater detail. A few double stars, nebulae, and star clusters, are indicated as examples.]

The Planets. Sometimes a very bright star is seen shining in the sky, which is not shown on any of the maps: the maps are not imperfect, however, and it will be found on comparing them with the sky that the stranger is very near the Ecliptic, and, therefore, simply one of the planets.* If the unknown star shines with a clear steady light, and at the same time is not far away from the Sun rising or setting a few hours before or after him), .it will probably be the planet Venus; or if very near the Sun, dull, and perhaps pinkish in colour, Mercury.

If it is shining with a bright clear light, and is situated at a good distance from the Sun—seen for instance near the south at midnight—it will without doubt be the giant planet Jupiter, the largest planet in the solar system. When the stranger appears as a very red star, it will doubtless be the planet Mars; and if seen shining with a dull greenish colour, it will be the ringed planet Saturn.

The ‘Inferior’ Planets (Mercury and Venus) move in orbits within that of the Earth, and being nearer the Sun, only circle the star sphere yearly as his attendants, swinging to and fro on each side of him, and never .attaining any great distance from him—Venus 470, Mercury only 290. When east of the Sun they are ‘evening stars,’ netting after him ; when to the west of the Sun, rising before him, they are ‘ morning stars.’

When, as seen from the Earth, they attain their maximum distance away from the Sun, to E. or W., they are •said to be at Greatest Elongation. The dates of Greatest Elongation—which may occur at any time during the year—are given in almanacs, but when it happens at one particular season of the year, the observing conditions .are better than at other times, while the season of the year six months later is unfavourable. Some years elapse before the favourable conditions return (p. 15). Each of these planets exhibits phases like those of the Moon.

The ‘ Superior’ Planets (Mars, Jupiter, Saturn, Uranus, and Neptune) have orbits lying outside that of the Earth, and differ from the ‘ Inferior’ planets in making a complete circuit of the star sphere on their own account, in periods from 2 years to 165 years. As, however, the Earth circuits round the Sun in one year only, it is evident that the Earth must outrun her slower-moving companions, so that once in every 53 to 57 weeks (Mars, 2 years) ■she overtakes them again, passing between them and the Sun, so that Sun, Earth, and planet are in the same line.

At this time, as seen from the Earth, the planet is in the opposite direction to the Sun, culminating about midnight, and is said to be in Opposition [to the Sun]: when in this position, the planet is best situated for

•    observation, being then nearer the Earth than at other times—though Uranus and Neptune are too remote to be much affected in brightness or size. There are, however, degrees of favourability.

Favourable Oppositions are those that take place in the neighourhood of a certain date, the nearer to it the better, and astronomers look forward to them because the planet is then not only about its nearest to the Earth, but also about its nearest to the Sun, so that it is both larger and brighter than usual. These very best

• opportunities, however, only come at long intervals, as will be seen by the following Table :—    circuits

Planet

Interval between Oppositions

Most Favourable Date

Least Fav’ble Date

Favourable Oppositions return

Star Sphere in

Mars

2 years

and 2 months

August 26

February

15 or 17 years (I941)

1*88 years *

Jupiter

I vear ✓

and 1 month

October 3

April

11-12 years (1940) "

11-86 „

Saturn

I year

and 2 weeks

December 20

June

29 years (1944)

29-46 „


The Position of the Ecliptic in the Evening'. If its relation to the celestial equator, in the merid’an ■ direction, is studied on the maps, it will be seen that after sunset, during the winter half of the year, it is always above the celestial equator, and in the summer half of the year always below it: it is vice versa before sunrise. As the planets are always near the Ecliptic, it is evident that when they culminate, on winter evenings they are . always high above the horizon; on summer evenings, low down, dimmed to some extent by haze, and by the greater thickness of the atmosphere. Mercury and Venus, however, are best seen at other times.

Mercury moves fairly rapidly, the interval between Greatest E. and W. Elongation being, about 44 days, .and from W. to E. 72 days, but as the maximum elongation is only 290 away from the Sun, this planet is rather difficult to see in temperate latitudes—the further away from the equator the worse—as he is never above the horizon after sunset for more than about two hours, and even under the most favourable conditions is so near the horizon that he is veiled by twilight and apt to be obscured by cloud or haze. In the N. Hemisphere he is best seen in April-May as an evening star, a few days before Greatest Elongation, and in Sept.-October as a morning star .a few days after Greatest Elongation—but longer in U.S.A., observers being much nearer the equator; and in the S-Hemisphere, where the corresponding times are July-Oct., Jan.-April. Favourable conditions recur every 6-7 yrs.

* There is a remote possibility that the very bright star might be a great new star, similar to those which appeared in 1901 and 1918. But as these were the first very bright new stars that had appeared for 300 years, the possibility is hardly worth taking into account.

Nearly all New Stars have hitherto only appeared in, or near, the Milky Way.


Venus is less rapid in her motion, the interval between extremes of elongation being about five months from E. to W., and fifteen months from W. to E. Attaining 470 away from the Sun, she may be above the horizon for some hours before sunrise or after sunset. The phases of Venus may be distinguished in a good opera glass.

Venus is the brightest of the planets, and attains maximum brilliancy (mag. - 4-3) every eight years, when Greatest Elongation takes place in December or March. Observers in the N. Hemisphere see Venus brightest as an evening star at a March Greatest Elongation, and those in the Southern Hemisphere at a December one.

Mars is of little interest for small telescopes, as his disc is small except at very favourable oppositions, being only about half that of Jupiter under the best opposition conditions, and much less at other times.

Jupiter.. His “belts” are clearly seen in a two- or three-inch telescope, and his four principal moons can be studied as they swing to and fro, and are eclipsed or occulted, or pass across his disc. . The flattening at the planet’s poles, and the darkening at the edge, are also quite apparent. The moons are visible in an opera glass.

Saturn. His rings are easily seen in a two-inch telescope, but only one of his satellites. At intervals of 14 and 16 years (from Aug. 1921) the rings come “edge-on” to the Earth and Sun, and are then too thin to be distinguished, for a time; or invisible, because the side presented to the Earth is not illuminated by the Sun.

Uranus; Neptune; Pluto; The Asteroids. None of these being brighter than the sixth magnitude,

are of no interest in small telescopes. Adonis, a very small asteroid, approaches at times within million miles of the Earth. Pluto may come within Neptune’s orbit. It is about the same size as the Earth.

The Sun. Sunspots large enough to be visible to the naked eye often appear; in looking for them the eye must be protected by a very dark glass, sold for the purpose, which is also necessary for a telescope. In the summer half of the year, the aperture should for safety be reduced to about an inch, by a cap of card with a hole in it. Alternately, a white screen may be placed a foot or more behind the undarkened eyepiece, and the solar image focussed upon it, when the spots can be studied—the penumbra, with its irregular outline, and dark central umbra, usually about one-third of the width of the spot. In a very large spot, “bridges” of brilliant light may sometimes be seen encroaching on the umbra. Sunspots take almost 14 days to traverse the solar disc from edge to edge, and re-appear after a similar period—if they do not disappear in the interval, as most frequently happens. Faculaz—bright patches—may usually be seen near the edge of the disc, and sometimes on the disc itself.

Sunspots wax and wane in number, in a period of about nj years. The time of minimum is reached about 6J years after the maximum, and the disc may be without spots for days at a time. Last maximum, 1928.

The Moon completes a circuit of the star sphere in 27^ days, thus travelling more than 13 times round the star sphere in the time that the Sun takes to move round once. This average time of the Moon’s complete circuit round the star sphere, however, is 2J days shorter than that in which her phases recur—29^ days.

The Ecliptic represents the Moon’s average path in the sky, but she swings backwards and forwards about 50 (ten times her own angular diameter) on each side of it, crossing it twice each 27-J days near the same points. The points of crossing are not fixed, but move westwards along the Ecliptic, completing the circuit in 18 J years.

Each phase of the Moon has its own ‘best seen’ time of the year, and (apart from the equinoxes and solstices), what is favourable in the N. Hemisphere is unfavourable in the Southern, and versa. The times are as follows:—

Age of Moon ..

3-4 days old. End of—

1st Quarter

Full

Last Quarter

Most FaFble

April N.; Oct. S.

Vernal Equinox

Winter Solstice

Autumn Equinox

Least ,,

Oct. N.\ April S.

Autumn ,,

Summer „

Vernal ,,

25-26 days old. End of— July 2V.; Jan. N. Jan. N. ; July S.

The craters, rays, and ‘ seas ’ of the Moon are well seen in a small telescope, but the craters are so numerous that a map of the Moon is desirable; a cheap one, giving the names of 300 objects has been prepared by the author (p.2). The best views are not obtained at Full Moon—when there is so little contrast that some great craters apparently disappear—but from young Moon to a few days before Full, or the similar ‘period after Full. Then the fretted ‘ terminator,’ or edge of the shadow, is very beautiful. ‘ Earthshine ’ (the ‘ Old Moon in the Young Moon’s arms’) is seen for 2 to 5 days on each side of New Moon. For best observing season, see Table above.

In using a map of the Moon, it is sometimes difficult to identify objects near the edge, as the Moon does not seem to be the same as the map. This is unavoidable, however, because the Moon, though always presenting the same face to us, wobbles, as it were, sideways and up and down to a slight extent, so that objects on the map near the edge pass out of view, or approach nearer the varying ‘apparent centre’ of the disc, which is rarely the true centre.

Occultations of stars by the Moon—that is, when she passes in front of them, hiding them from view— are very interesting phenomena, especially when the star is bright; an opera glass or telescope is advantageous. The disappearances (instantaneous) take place on the east side of the Moon, re-appearances on the west side;* the Moon’s motion towards the star is approximately at right angles to the line drawn between her horns.

Only those stars can be occulted that lie in what may be termed the Moon’s ‘Zodiac’ (the band 5J0 on each side of the Ecliptic. The same star may be occulted several times in successive months, then cannot again be occulted for 18 years, owing to the slow progressive annual change in the Moon’s monthly path among the stars.

* See Note p. 16 as to reversal with astronomical eye-pieces.

16    CELESTIAL OBJECTS FOR OBSERVATION.

t

Double Stars. Many of these are visible in a small telescope, and sometimes the components have different colours. The following are seen divided in a 2-inch telescope, many of them in a i or ij inch instrument.

Andromeda 7

Bootes €, £, 7T

Cassiopeia a

Corvus...

5*

Eridanus 0

Lepus ... a, 7

Perseus... e, f

Aquarius f

Canes Ven. a

Centaurus a, 7

Crux ...

a, 7

Gemini a, 5

Libra ... a

Pisces ... a

Ara 7

Cancer ... 1

Cepheus ß, d

Cygnus

ß

Hercules a, d

Lyra

Piscis Aust, ß

Argo ...7,7r,v

Canis Maj. e

Cetus ... 7

Delphinus

7

Hydra e

Orion ...Ô, 1, X

Sagittarius ß9 jul

Aries ... 7

Capricornus a

Corona Bor. f

Draco ...

e, V

Leo ... a, 7, l

Pegasus... e

Scorpius a, ßf a


Serpens d, 0 Toucan j8, Virgo ...    7

Ursa Maj. £ i ,, Min. a

Star Clusters are most exquisite sights in a small telescope, the stars glittering like diamonds sparkling on black velvet. As, however, they are not in general near enough to bright stars to be easily identified, they lie rather outside the scope of this book, but the following may be mentioned, in addition to the Pleiades, Hyades, and Prsesepe, described on pages 22 and 24. Those marked J are not visible in Britain or U.S.A.

Cassiopeia : close to d, towards e. Hercules:    way from rj to

Perseus : about halfway between Algol and 7 Andromedæ.


Centaurus :J nearly halfway from jj, Centauri to 7 Crucis ( = w Centauri). Toucan one quarter of the way from Hydri to Achernar, on Pavo side.


Gemini: just north of tj, near the line to 6 Aurigae.

Monoceros : one-third of the distance from Sirius to Procyon, towards Orion.

Variable Stars. Algol and    Mira,the most interesting of the variable stars, are described on page 31

8 Cephei (Map A) has given the name ‘ Cepheids ’ to a type of variable star which is of very great importance in stellar measurements; it varies from the third to the fifth magnitude in about 5 days—probably due to pulsations of the star. [3 Lyrae varies in a different fashion in a period of 13 days, and gives the name to another type of variable, the * Lyrids.’ Algol, in its turn gives the name to the ‘Algolids,' while Mira is a ‘ long-period variable.’ The notable rj Argus, near the Southern Cross (not seen Britain or U.S.A.), has great but very irregular fluctuations.

Nebulae. Scattered over the heavens are faint patches of milky light, too faint to be interesting except in large telescopes. Some have been resolved into clusters of very faint stars, like the Great Andromeda Nebula (p. 31), which is visible to the naked eye; others are known to be masses of glowing gas, like the Great Nebula in Orion, close to 1, which is within the reach of a small telescope (see p. 23).

The Zodiacal Light. This is a faint cone-shaped light—averaging twice the brightness of the Milky Way—which extends from the horizon along the Ecliptic for about 90 degrees—from west to east after sunset, or fiom east to west before sunrise. Its position in the sky should be traced by the path of the Ecliptic in the circular maps, otherwise the glow of twilight is apt to be mistaken for it. This Light is supposed to be due to the light reflected from meteoric bodies near the Sun, and is best seen (in Britain, mostly ‘ only seen ’) about the equinoxes, when the Ecliptic is most nearly vertical to the horizon, and about due W., soon after sunset (or before sunrise, E.), namely:—N. Hemisphere, evening, March-April; morning, September-October; vice versa, S. Hemisphere. U.S.A. and Southern Hemisphere observers, being nearer the equator, can see it during a longer period.

Meteor Showers. The more important are given below, with the nearest bright star within 50 or 10° of their ‘radiant’* in the constellation from which they are named: the shower may begin before or end after the date given. Jan. 2, Quadrantids (¡3 Bootis); Apr. 20, Lyrids (a); Jul. 25, Aquarids (§); Aug. 10, Perseids (rj); Oct, 18, Orionids (v); Nov. 13, Leonids (y); Nov. 17, Taurids (e); Nov. 27, Andromedids (7); Pec. 11, Geminids (a).

Notes On Observing. Observations should be made as near culmination as possible to avoid loss of light by atmospheric absorption, which is very great near the horizon. Compared with its zenith brightness, a star is a whole magnitude fainter when only 10 degrees above the horizon, and two magnitudes fainter when only four degrees above it; this is independent of the effects of haze, which still further reduces the brightness.

The following Table shows what is within the reach of good telescopes of various sizes, under the best seeing conditions, when the air is still and clear; ordinary conditions reduce the limits.

Diameter of object glass ...    1 in. l^in. 2in. 2|in. 3in.    ... 1 in. 1^ in. 2in. 2|-in. 3 in.


Faintest star shown, mag. 9th 10th 10J 11th llj I Closest double star divided, 4^"


2i"


1 3"

G


il" x2


Note that when using an ‘astronomical’ eyepiece the object is shown upside down, and the directions are reversed—east, for instance, being on the west side of the observer, and vice versa. Ordinary telescopes and opera glasses, however, show objects in their natural position. The astronomical eyepiece gives a brighter image, for, to make the image right way up, ordinary telescopes require extra lenses, which absorb some light.

Estimating Angular Distances on the star sphere. The Moon is approximately half a degree; also the Sun. 5°= approx, a to (3 Urste Maj., or a to ¡3 Centauri. 10°, 7 to e Ursse Maj., or (3 Crucis to (3 Centauri.

The Greek Alphabet:—

Letter Name

Letter Name

Letter Name

Letter Name

Letter Name

Letter Name

8 ... Delta

71 ... Eta

k ... Kappa

V

... Nu

nr ... Pi

t ... Tau

e ... Epsilon

0 ... Theta

X ... Lambda

... Xi

p ... Rho

v ... Upsilon

( ... Zeta

i ... Iota

P- ... Mu

0

Omicron

or ... Sigma

<J> ... Phi

Letter Name

X ... Chi j ... Psi to ... Omega


Letter Name

a ... Alpha

(3    ... Beta

7 ... Gamma

V. Finding Celestial Objects by Star Maps.

Locating Planets, Comets, &C. Maps I to XII suffice for identifying the stars and constellations on any evening; but are not convenient for locating planets, &c., among the stars, from almanac or newspaper information —as this requires star maps with lines of Right Ascension ’ and * Declination,’ the astronomical terms corresponding to terrestrial ‘longitude’ and ‘latitude.’ Map B, and Maps A or C, showing these lines, have therefore been provided, which, aided by the following paragraphs, take the reader a stage further in astronomical knowledge.

Declination. As the star sphere has poles, and an equator—the Celestial Equator or Equinoctial—half-way between the Poles, we can therefore describe a position on the star sphere in exactly the same way as we locate a place on the Earth’s surface by its latitude and longitude. We can say, for instance, that Altair is 8| degrees north of the celestial equator, or that Sirius, is i 6bdegrees south of the same reference line.* Instead of calling these respective figures the star’s latitude,! however, astronomers term them its Declination (contracted, ‘Dec.’).

Right Ascension (contracted, ‘ R.A.’), the equivalent, on the star sphere, of terrestrial longitude, is not usually stated in degrees—except for meteor observations—as Declination is, but in hours, minutes, and seconds of sidereal time, a clock reading being more convenient, as explained below, and the same thing in the end.

The First Point of Aries. Just as Greenwich is now the universal ‘ 0° ’ of terrestrial longitudes, a certain point in the sky, situated on the celestial equator, has been agreed on as ‘0 hours ’ of Right Ascension. This zero starting-point is called ‘ The First Point of Aries,and its approximate position in the sky at any time can be found by drawing a line from the star a of Andromeda to the star y of Pegasus—one side of the ‘ Great Square of Pegasus’ (see p. 20)—and extending it onwards for a similar distance. The exact position of this Point is shown on the maps, being the point where the Ecliptic intersects the Celestial Equator (or ‘ Equinoctial ’) in Pisces.

The Stars always Visible or Invisible. This depends on the observer’s latitude, and the star’s Declination. Subtract the latitude of the observer from 90°, the answer is his “ co-latitude,” used as follows :—

Declination greater than the co-latitude of the observer These stars, if on the far side of the Celestial Equator, never rise; if on the near side, they never set.

Declination LESS than the co-latitude of the observer :—For stars on the far side of the Celestial Equator, subtract the Declination from the co-latitude ; the answer is the number of degrees attained above the horizon at culmination.

Almanacs, &C. The R.A. and Declination of the planets are given in Almanacs, and those of comets and new stars in the daily newspapers. Whitaker’s well-known Almanac is one of the best; in addition, it contains copious notes on celestial objects. The Annual Handbook of the British Astronomical Association may also be mentioned, and the Abridged Nautical Almanac. In the United States, the ‘World Almanac’ is similar to ‘Whitaker.’

Why Right Ascension is measured in Time. To understand why astronomers prefer this form, let us go out at 9 p.m. on November 6th. Finding the First Point of Aries by means of the Great Square of Pegasus, we see that it is due south (S. Hemisphere, north) or ‘culminating’. The star a of Andromeda is also at culmination, being practically on the zero meridian. Two hours later we go out again: the First Point and a Andromecke have passed westwards, and now y of Andromeda and Hamal in Aries are culminating. An hour later, three hours after the start, Algol, in the constellation of Perseus, culminates in its turn, and so on for any other star, until, after 23 hrs. 56 min. 4 sec., the Earth having made a complete revolution on its axis, the First Point of Aries returns to the meridian, and the cycle begins over again. As the First Point has travelled 360° in 24 sidereal hours, it is obvious that 1 hour’s motion must be the same as 150 angular motion (= 360° -p 24); 4 minutes the same as i°; &c.

Now by noting the hour when each of these stars culminated, as compared with the First Point of Aries, we have really been finding (roughly) their Right Ascensions. The Right Ascension (usually written contracted “R.A.”) of a Andromedse is 0 hours, because it culminates or “transits” at the same time as the First Point; the

R. A.S of both y Andromedae and Hamal are 2 hours, because they each transit two hours after the First Point, and that of Algol is 3 hours, because it transits 3 hours after it, and so on for every star. Of course astronomers take the time more accurately than in these rough examples, reading it to minutes, seconds, and even fractions of a second: the ‘ hours,’ ‘ minutes,’ and ‘ seconds,’ on the sidereal clocks they use are each a small fraction less than those of ordinary clocks, to suit the revolution of the star sphere in 23 hrs. 56 mins. 4 secs., ordinary time.

Knowing, therefore, the Right Ascension of any celestial object, i.e., how many hours, minutes, and seconds, it “transits” after the First Point of Aries; knowing also its Declination, or distance in degrees, north of south of the Celestial Equator, we locate that object exactly on the star sphere, and among the stars by Map B.

* The Equinoctial is highest above the observer’s horizon when due South (S. Hemisphere, N.), and always cuts the horizon due E. and W.

f The terms latitude and longitude are also used in astronomy, but unfortunately in a different sense from that in geography. By ancient usage, they were utilised for describing measurements north and south of, or along, the Ecliptic, instead of the Celestial Equator, so that other names had to be provided for measurements referred to the latter. A star’s or planet’s “latitude5’ is its distance in degrees N. or

S.    of the Ecliptic ; its “ longitude,” its distance from the First Point of Aries, measured in degrees along the Ecliptic, not the Celestial Equator,

*

X Also known as ‘The Equinox,’ and defined as the position occupied by the Sun’s centre on March 20-21 each year, at the instant it crosses the Celestial Equator at the vernal equinox. Long usage sanctions the use of ‘Vernal Equinox’ for ‘ The Equinox,’but ‘Vernal’ is best restricted to the March 20-21 position. Each year this point is about 1 /70th of a degree further west on the Ecliptic than it was a year before—in 37 years equivalent to the angular breadth of the Moon in the sky. This movement of the First Point is the ‘ Precession of the Equinoxes.’

B1 h}S

The PJaivses of the Principal Stars.

Also the corresponding Greek letter. The spellings vary, as Betelgeux, Betelgense, and frequently there are alternative names. Stars marked £ are not visible in Britain and the United States. For meanings of the constellation names, see last page.

Constellation. Letter. Name.

Andromeda a ...Alphei'atz

,.. Mir a ch ... Almach


Aquarius


Aquila


Argo

Aries


Auriga


Bootes


ß

7

a

ß

s

a

ß

7

a

a


Sadalmelik Sadalsund .    Skat

.    Alt air

.    Alsha

.    Taraz

Canopus Marnai


ß    ... She rat an

7 ... Mesartim


a ... Cap ella ß Menkalin a. ...    Arc

...

... Izar Cor Caroli ,.. Sirius ,.. Mirzam ,..    P

.. Gomeisa


ß


Constellation. Letter.

Cassiopeia a*

ß*

• • • • • •

Cepheus a*

.. ß

-X-


Constellation. Letter.

Gemini..; 8 .,


Ñame.

Schedar .. Chapk

.

. Errai . Menkar .

.    ( Baten Kaitos

. o ... Mira Columba a ...    Phact

CoronaBor.a ... Alphecca Corvus ... a ... Alchiba ...    8 AIgorib, AIgores

Cráter ... a ... Alkes Cygnus... a DArided

......(3 ... Albireo

a*... Timban ¡3 ... Alwaid 7 ... Etanin a t... Achernar (3 ... Cursa 7 ... Zaurak a ... Castor ¡3...    Pollux

7 ... Alhena


Cetus


Draco


7


a

ß


• • •


Constellation. Letter.

7

e    ..

i••

a    ..

...    ... f3 ..

Pisces ...    a    ..

Piscis Aust. a Sagittarius e Kaus Australis Scorpio    a    ...    Antares

Serpens    a

Taurus ... a Aldebaran * * * • * • [z •.. ... Phalli ...    r], (Pleiad) Alcyone

Ursa Major a*... Dublie

...... (3*..Merak

• ••    •••    7    •••    Phecaa

...    ...    a    .


Name,

Algenib


Name.

Wasat

......    e    ... Mebsuta

Hercules    a    Ras Algethi

...    ß    Korneforos

...    a    ... Alphard

...    a    ... Regulus

ß Deiieb, Benebola ...    7    Algeiba

...    8    ... Zosma

...    a    ... Arnab

a Zubenel Genubi ß Zuben el Chamali 7 Zuben el Hakrabi ...    a    ... Vega

...    ...    ß    ... Shell ak

...    ...    7    ... Sulaphat

Ophiuchus    a    Ras Alhague

ß ... Cebalrai a Betelgeux ß ... Rigel

7    ... Bellatrix

8    ... Mintaka e ... Alnilam a ... Markab ß ... Scheat


Hydra

Leo


• • •


• • •


Lepus

Libra


Lyra


Pegasus


• mm


Perseus...


. Moman Mirfak ... Algol Kaitain Fomalhaut


.. Megrez .    A Ho th

Benetnasch

.

. Polaris .

. Spica . Zavijava

- [ e

How to Use the Circular H^aps,

Maps I to XII represent the position of the constellations visible on the day and at the hour stated at the bottom of each. The circumference represents the horizon, with the principal points of the compass inserted, and the small cross in the centre of each Map is the part of the sky directly overhead, or ‘ Zenith ’ as it is called.


Canes Ven. a Canis Major a • • •    • • •

Canis Minor a

......ß

Capricornus a2Secunda Giedi

8


• • •


• • •


Eridanus


Gemini...


Orion


• •


Pegasus


e*


t


\r

7T


V

L


Ursa Minor a* ... ß*

• • (X

... ß


Virgo


(a).    Face west, say, then find the Circular Map which has the required date    and hour (or the nearest) at the foot.

(If “Summer Time,” first deduct i hour from the clock time; thus    for May 22, 9 p.m., the Map is that

for May 22 at 8 p.m. = Map 7 : for 10 p.m., May 22, the stars will be intermediate between Maps 7 and 8 )

{b).    Holding up the map at right angles to the ground, and using the zenith    + as centre, turn the map round till

‘West’ is nearest the ground; the western stars between the horizon    and zenith can then be identified.

For the Northern stars, face north, and keep ‘North,’ nearest the ground, and similarly for any other direction.

The stars near the map-horizon may be quite invisible in the haze; but observers nearer the equator than the latitude for which the maps are drawn, see the stars in the meridian direction higher above the horizon than in the map (Map B is best for these stars); they lose, however, an equal portion of the Polar stars.

Note.—For uniformity, and ease of reference, each map has the same range of hours, 5 p.m. to 5 a.m.: in summer, however—when the Sun sets late and rises early—in the earlier evening hours or later morning hours, the stars, though above the horizon, will be lost in daylight, in proportion as the observer is distant from the equator.

The Constellations Round the ^Jorth Pole.

Map A depicts the North Polar stars—which never set in Britain, or in North America north of 50°; but which are never seen in the S. Hemisphere south of 50°. The most conspicuous North Polar constellation is Ursa Major, the Great Bear, also called the ‘Great Dipper’ (i.e., ladle), in the United States. The Egyptians called it the Hippopotamus (the bear being unknown in Egypt), but it was recognised as a bear by the Greeks, Persians, &c., and when America was discovered, the Northern Indians knew it as the (Polar) Bear, showing that they had either independently recognised it themselves, or had been in some way connected with the Eastern world. Near Ursa Major is the long winding constellation Draco; beyond it, on the Milky Way, are the constellations Cepheus and Cassiopeia. Near the centre of the Map is Ursa Minor, the Little Bear, with the Northern Pole Star, Polaris—not exactly at the Pole, but a little more than i° away from it, or about twice the diameter of the Full Moon in the sky. The Southern Pole Star, cr Octantis, is almost exactly halfway between

Achernar and ¡3 Centauri (Map C); it is less than a degree from the Pole, but being only magnitude 5^ is very faint.

* Not visible in the Southern Hemisphere, in latitudes south of 35° S.

«    The Constellations Round the Poles.

cs    At the dates round the edge (holding each Map so that the required date is nearest the ground), that point in

the sky is, AT MIDNIGHT :—Northern Hemisphere, DUE NORTH ; Southern Hemisphere, DUE SOUTH.

For 10p.m., use the same dates in the PREVIOUS month; for 8p.m., use the dates of TWO months before,

and so on. 11 p.m., 9 p.m., &c., are halfway between. (See pp. 18-19).

MAP A (N. Hemisphere, p. 18).    MAP C (S. Hemisphere, p. 19).


Maps A & C


Map A shows the stars which never sink below the horizon in Northern temperate latitudes, but revolve round the Pole in the same time that the Earth rotates on its axis, and in the opposite direction to the hands of a watch. In Southern temperate latitudes, only those near the edge are ever seen.

Map C shows the stars which never sink below the horizon in Southern Temperate latitudes, but revolve round the Pole (P) in the same time that the Earth rotates on its axis, and in the same direction as ns the hands of a watch. In Europe and the northern United States, none of them rise above the horizon.

A retar us


llenuhJs


DELF*Vi


L CUftOf

jPomujc ..i


RIGHT ASCENSION


roevott<


MONO GtHOS


irius


MAJOR


RIGHT ASCENSION


. -----------¡

■ •

■ v

■ O

.0 -

Y ,

o

* V ■ •

) t

' - . . ■

t .

!v "... '

'/

; •

. ' ' i;

p

* / o .

'

’ . . . . ■. a

..,’

;- . ■ -

•%

* , . i .

• ■ * T

r- * /

1 * * * •

y


FomaJhaut

Map B, in two overlapping portions, shows the stars from the horizon to nearly overhead, in the direction of the meridian, at 9 p.m., on the dates mentioned at the foot. The Ecliptic is shown dotted.

For each hour earlier than 9 p.m., the stars whose Rt. Ascension is 1 hour less will be on the meridian; or each hour later, those whose R.A. is 1 hr. more. (If “ Summer Time,” deduct 1 hr. from clock Time). n. & s. Const, page t8b    In the Southern Hemisphere, hold the Map upside down.

RIGHT ASCENSION

CAN


rocyoh


BeJ~dqcJix *


'P-*


MONOC LAOS

Sin/is

MAJOR

RIGHT ASCENSION

Map B is also intended for locating planets, &c., among the stars, from the positions given in Almanacs. Thus if the Rt. Ascension of Jupiter is given as “ R.A. 4 hrs. 30 min.,” and its Declination as “21° 56 N.,”

it will be seen from the map that it is just north of Aldebaran, in Taurus.

n. & s. Const, page 18c    in the Southern Hemisphere, hold the Map upside down.


Map D


The Celestial Equator, 4000 Years ago (Compare with Map VIII., p.27)

The Old Constellation Figures


Map B—in two portions, with considerable overlap—is chiefly intended for enabling a planet or other object to be located among the stars, when its Right Ascension and Declination are known. The Ecliptic is shown dotted, and for clearness, only a few of the Greek letters; other letters can be found in Maps I. to XII.

Observers nearer the equator than the latitude for which Maps I. to XII. are drawn, will find the Map useful, as it shows the stars seen low down near the meridian, which, in the maps, are not far below the horizon.

Should the observer’s latitude be greater than 450 N. or S., some of the stars shown on the Map (which includes those to about Dec. 450 N. or S.) will not rise above his horizon, in accordance with the rule given on p. 17.

In the Southern Hemisphere the map must be held upside down, as the northern stars are nearest the horizon.

__

The Constellations Round the South Pole.

Map C represents that part of the Southern heavens which is always visible in the temperate latitudes of the Southern Hemisphere, but which is always below the horizon in the latitude of Europe or the United States. The Southern Cross—which rivals any group of stars among the Northern constellations—replaces the Great Bear in pointing to the Pole Star; its two stars a and 7 are the Southern ‘ Pointers,’ for a line from 7 through a points out the very faint Southern Pole Star, <r of Octans. Crux, the Cross (a modern constellation, added in 1679), is near the top of the map, just on the edge of the Milky Way—which is particularly bright in the Southern Hemisphere, and has many rifts and branches; in this part of its course it is completely divided across in Argo.

Other conspicuous stars, not seen in Europe or the United States, are Achernar, at the south end of Eridanus, and    Canopus, the brightest star in the large constellation of Argo, which contains many bright stars; both these

stars, however, just show above the horizon in the extreme south of the United States. Near the Cross are a and f3 Centauri; the former is the nearest known star. The two Magellanic Clouds, Nubecula Major and Nubecula Minor, still nearer the Southern Pole, resemble detached portions of the Milky Way; examined with the telescope, these nebulous masses are found to consist of small stars, clusters, and nebulae of every description


It will be observed that many of the constellations in the Map have modern names, which show us that the division of this part of the heavens into groups must have been of comparatively recent date. In fact it is only within the last 300 years or so that the constellations near the South Pole have been named. Bayer named 12; Bartschius, 4; Royer, 4 (including Crux); Hevelius, 9; Halley, 1; Flamsteed 2;

La Caille, 14 : some of these, however, were not accepted by other astronomers, and many were modified to a less cumbersome form (see p. 32).

Why there are Modern Constellations. Naturally, it may be asked, how is it that this particular part of the heavens has not been divided into constellations before? We see in other parts of the heavens groups that were named thousands of years ago, and know that some of the constellations which are familiar to those living in the Northern Hemisphere, were known to the Chaldseans long before Greece and Rome were in existence. Now, when these (modern) constellations are carefully examined on a celestial globe, and a line drawn round so as to encircle them (as in Fig. 6), it is found that the boundary line is (roughly) a circle, and that the centre of this circle falls in the constellation of Hydrus, near to the star Alpha. At first sight, it would seem that this will not give us any information as to why this part of the heavens was not divided into constellations in ancient times. But when we find that about 4000 years ago the South Pole of the Earth pointed to the very centre of this circle containing the modern constellations, we see that the stars composing

these constellations, being then near the South Pole, would, in a certain latitude, never appear above the horizon, and would thus be always invisible, just as the constellations near the North Pole are invisible in similar southern latitudes at present. These stars then, having never been seen by those who named the ancient star-groups, remained unnamed till they were at last seen in modern times, when explorers travelled further to the south.

Where the Old Constellations were Named. As this circle is about 40 degrees in radius, all the stars that would be invisible to those who named the constellations would be within 40 degrees of the South Pole, so that 40 degrees North—the latitude where stars situated within 40 degrees of the south pole are invisible— will probably be the latitude of the country whose inhabitants first named the star-groups. But as the stars cannot be distinctly seen very near the horizon, we may safely say that the latitude would be a few degrees to the South of this, so as to make the Southern stars appear a little higher in the heavens. Thus the probable latitude where the star-groups were first named, would be about 36 or 37 degrees North, which is the latitude of Chaldsea; and this, too, points to the Chaldseans as being the people who first divided the heavens into constellations.*

* See Note foot of page 4.

N this map, and at the times indicated, the constellation of Crux, the Cross, will be seen almost due South, and at the lowest part of its diurnal course. It is easily recognised by its four principal stars forming a conspicuous Cross, and a line drawn from y through a points toward the South Pole of the heavens, a point indicated by the 5th magnitude star cr, Octantis (shown on Map C, p. 18). a Crucis is a fine double star whose components are both of the 1st magnitude. West of the Cross is Centaurus, with its brilliant star Canopus (Map 7), above which is Triangulum.



Further West still are Ara, the Altar, and the zodiacal constellation, Scorpio, the Scorpion, with its brightest star, the ruddy Antares. Above Ara are the small constellations Pavo and Indus; while at a lower altitude, and South-South-West, is Sagittarius, the Archer; above this, in the West, is Capricornus, the Goat, a constellation of the Zodaic. Between this constellation and the zenith, the bright star, Fomalhaut, the principal star in Pisces, will be seen ; to the left of which, and about the same distance from overhead, are the two unimportant constellations Grus and Toucan.    _    ,

r    iTiT    .    .    I he Southern

Midway between the West and the North-West, and a little above the horizon, there '    Cross,

will be observed three stars in a line, the brightest being in the centre; this star is called Altair, the principa star in Aquila, the Eagle. To the left of Aquila are two small groups, Delphinus and Equuleus, the little Horse, above which is Aquarius, the Water-Bearer, which is the second last constellation of the Zodiac. Below Aquarius, and now nearly North, will be noticed a large square, formed by four bright stars; this is called the “Square of Pegasus,” though only three stars belong to the constellation of Pegasus. The star forming the North-East corner of the square was formerly called both 8 Pegasi and a Andromedse, but astronomers now only retain the name of a Andromedae, from which circumstance there is now no star called 8 in Pegasus. This constellation of the Flying Horse (Pegasus) was anciently called “Nimrod’s Steed;” its principal stars are Markah (a), Scheat (/3), and Algenib (y). Andromeda, the Chained Lady, will be seen below and to the right of the square of the Pegasus ; while to the right of Andromeda will be noticed the constellations Triangulum and Aries the Ram. Above Aries is the barren constellation of Pisces. The asterism is delineated in old star globes by two fishes linked together by a ribbon, the one fish lying parallel with the top side of the square of Pegasus, and the other with the right side of the square.

Looking now nearly North-East, and midway between the point overhead and the horizon, the extensive constellation of the Whale, Cetus, will be observed. The star (o) in the neck of the Whale is called Mira, the epithet “wonderful ” being given to it on account of its great variation in brilliancy, over a period of about 330 days (see note below). Underneath Cetus, and not yet completely above the horizon, is Taurus, the Bull, with its bright ruddy star, Aldebaran (Map 3), and its naked eye cluster of stars, the Pleiades. Nearly due East the brilliant constellation of Orion will be seen, the three conspicuous stars in a line forming “ Orion’s Belt ” having just risen above the horizon. Beside Orion is Lepus, the hare, while above it will be seen the long straggling constellation of the River, Eridanus; its principal star, Achernar, now being nearly South and at a high elevation above the horizon. Between this star and its zenith is Phoenix, its three principal stars forming a triangle.

A very conspicuous star will be seen between the East and South-East, this is the brilliant Sirius (Map 5), in Canis Major, part of which constellation has not yet appeared. Above Canis Major there is situated the small star group of Columba, the Dove. Stretching along the horizon, and reaching nearly to the South, the large constellation of the Ship, Argo, will be observed, its leading brilliant, Canopus, now being exactly Southeast, and underneath the unimportant constellations Dorado, the Sword-Fish, and Reticulum, the Net; while to the right of Reticulum, and twisting upwards near to the bright star Achernar, will be seen Hydrus, the Water-Snake. Canopus is the second brightest fixed star, Sirius being the brightest; it is situated at a vast distance, perhaps 460 light-years, and must be of immense size, for it is 45,000 times more luminous than the Sun.

Mira is quite invisible without a telescope for about five months, sinking to magnitude 9, then becomes visible to the naked eye for some six months, at maximum attaining fifth to third magnitude—occasionally, the second magnitude—for a week or two, after which it disappears for another five months.

Some interesting facts have recently been ascertained. At maximum it is more than a thousand times brighter than at minimum, yet when both light and heat sent to us are measured, the strange fact emerges that the increase is almost entirely in the light, the extra heat received at maximum being only 2^ times the amount at minimum. The increase in brightness may be due to periodic outbursts of hydrogen gas.

The angular diameter of Mira is 6o/iooths of a second of arc, equivalent to 125-240 million miles, according to different estimates of distance. It was formerly thought that a faint companion must be near it, and this has now been found, it being a white dwarf, like the companion of Sirius.

S20

Map 1. The Constellations for October and November.

Hxnos

Map 1. THE STARS VISIBLE AT THE FOLLOWING DATES & HOURS (Rt. Ascension 0 hrs. on Meridian)

Date p.m.

Sept. 21, 12*0 „    26, 11-40

Oct. 1, 11-20

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Oct. 6,

11-0

Oct.

21,

10-0

Nov.

6>

9-0

Nov.

21,

8-0

Dec. 6,

7-0

Dec. 21,

6-0

» 11,

10-40

n

26,

9-40

»

11,

8-40

n

26,

7-40

» 11,

6-40

,, 28,

5-30

w

10-20

»

31,

9-20

»

16,

8-20

Dec.

1,

7-20

» 16,

6-20

Jan. S,

5-0

AFTER MIDNIGHT. Sept. 14,12-30 a.m.; Sept.6,1 a.m.; Aug.21, 2a.m.; Aug. 6,3 a.m.; Jul.22, 4a.m.; Jul.15, 4 30 a.m.; Jul.7,5 a.m.

C14/18

WEST


Map 2. The Constellations for November and December

Hinos


EAST


north

Map 2. THE STARS VISIBLE AT THE FOLLOWING DATES & HOURS (Rt. Ascension 2 hrs. on Meridian)

Date p.m.    Date p.m. Date p.m. Date    p.m. Date    p.m. Date p.m. Date p.m.

Nov.

6,

11-0

Nov.

21,

10-0

Dec.

6,

9-0

Dec.

21,

8-0

Jan.

5,

7-0

Jan.

20,

6-0

99

11,

10-40

,,

26,

9-40

99

11,

8-40

99

26,

7-40

99

10,

6-40

,,

27,

5,

5-30

99

16,

10-20

Dec.

1,

9-20

99

16,

8-20

99

31,

7-20

99

15,

6-20

Feb.

5-0


Oct. 21, 12*0 „    26, 11*40

„    31,    11*20    „    --,    *1    ""    »    *”I    --»    --1    • —w 77    7    --- ---- -7    - -

AFTER MIDNIGHT. Oct. 14«, 12-30 a.m.; Oct. 6, i a.m.; Sept. 21,2 a.m.; Sept. 6,3 a.m.; Aug. 21,4 a.m.; Aug.l4,4,3oa.m.; Aug.6,5a-tn.

RUX, the Cross, has now moved a little to the East of the South ; while a and ¡3 Centauri now occupy its former position. Above a Centauri is Triangulum, to the right of which is Ara. Scorpio has now set, and Sagittarius is rapidly disappearing; above Ara will be seen Pavo, and Indus, while above Pavo, is Toucan. In the West we see Capricornus nearing the horizon ; above it is Piscis, and Grus. Aquarius, with Equuleus underneath, is to the right of Capricornus, and midway between the West and the North-West. The Flying Horse, Pegasus, has now passed the North-West, the Great Square being somewhat tilted up. Andromeda lies horizontal, and near the horizon between the North-West and the meridian. This constellation is one of a group comprising the constellations Cepheus, Cassiopeia (which we never see in our latitude), Perseus, and Cetus. According to Grecian mythology, Cepheus was a King of ^Ethiopia, and Cassiopeia his queen. Andromeda was their daughter, whom Cepheus, in order to preserve his kingdom, was obliged to chain to a rock to be devoured by a sea-monster, which is represented in the constellation of Cetus; but Perseus, on his return from the conquest of the Gorgons, rescued her, and turned the monster into a rock by showing it the head of Medusa.


Above Almach (7 Andromedse), and a little to the West of the meridian are the constellations Triangulum and Aries,_Triangulum being underneath. Aries is the first constellation of the Zodiac. Manilius thus

describes it:—

“ First Aries, glorious in his golden wool,

Looks back and wonders at the mighty Bull.”


More than 2000 years ago the middle of this constellation was on one of the Equinoctial points (/.<?., the points where the Equinoctial cuts the Ecliptic), from which it has been called “ the first point of Aries.” But owing to the precession of the Equinoxes, or the swaying motion of the axis of the Earth round a perpendicular to the Ecliptic, the Equinoctial points have, since that time, moved to the West on the Ecliptic about 30 degrees, which gives the whole heavens an apparent motion round the poles of the Ecliptic in about 25,900 years.* Thus Aries 2000 years ago occupied the same position with regard to the Equinoctial as Pisces now does,—(Fig. 7), but since then it has apparently moved to the West a whole sign; so that the constellation of Aries is now in the sign of Taurus, Taurus in Gemini, Ac.

Mesartim, the 7 of Aries, is interesting from the fact that it was one of the first double stars that was discovered. Dr. Hook, while observing a comet in 1664 accidentally «came across this star with his telescope, and found that it consisted of two stars close together. There are now several thousands of double stars, not only detected, but their apparent distances accurately measured; spectroscope detects many others too close for visual measurements.

To the East of the North, part of Perseus will be seen, close to the horizon; while above Perseus and nearly North-East, is Taurus, now completely risen.

To the right of Taurus will be observed the conspicuous constellation of Orion, his “ star gemmed belt ” shining brilliantly. Underneath Orion, and just above

the Eastern horizon, will be noticed the bright star, Procyon, the leading star in Cams Minor. Above Orion, and winding upwards past the point overhead, will be observed the long constellation of the River, Eridanus, one of the old asterisms, its most conspicuous star, Achernar, now being a little to the South of the zenith. Canis Major, with its leading brilliant, Sirius, “ the Dog Star,” will now be seen due East, and at a fair altitude above the horizon. To the right of this constellation is the Ship, Argo, its principal star, Canopus, is now exactly South-East, and midway between the zenith and the horizon; while to the left of Canopus are the small constellations Dorado, the Sword Fish, and Reticulum, the Net; and farther in the same direction will be seen Hydrus, the Water Snake. Between the Sword Fish and Hydrus, there wall be observed a faint nebulous mass, just like a small detached portion of the Milky Way, this is one of the Magellanic Clouds; it is called the Nubecula Major, the other one, seen near /3 Hydrse, is the Nebecula Minor. When these nebulous masses are examined with the telescope, they are found to consist of small stars, clusters, and Nubulae of every description.

Algol. The star ¡3 of Perseus was named Algol, 1 The Demon/ by the Arabs, who probably noticed—but could not understand—its vagaries in brightness. Every 2 days 2 of hours, it drops from about the second magnitude to the fourth magnitude in a few hours, and then in a similar period regains its ordinary brightness. Tlfis is due to its regular partial eclipse by another star of lesser brightness, revolving round Algol as primary.

New star in Perseus. In 1901 a great new star appeared about halfway between Algol and 3 of Perseus, but slightly in the Pleiades direction. It was the brightest new star that had appeared since Kepler’s star in 1604, and attained a brilliancy rivalling Canopus for a short time, then it gradually laded away.

RA, the Altar, is now due South, low down on the horizon, Triangulum and Pavo being directly above. Toucan, and Grus, have now moved to the South-West; immediately above Toucan will be seen the bright star Achernar(a Eridani), between the constellations Hydrus and Phoenix. Between the South-West and the West, we see that Capricornus, and Aquarius have nearly disappeared; while above    these constellations is the bright star    Pisci),


rapidly    approaching the horizon.    Nearly North-West, the great square of Pegasus has    all but

disappeared; and to the left of it will be seen Andromeda, the Chained Lady, now about to dip below the horizon. Above Pegasus is the dim constellation of Pisces, the Fishes; whilst to the right of Pisces will be observed Aries, the Ram, and Triangulum, the Triangle.

A little to the West of the meridian, low down on the horizon, and partly below it, will be seen the constellation of Perseus, the rescuer of Andromeda. [The star Algol,, “The Demon,” in this constellation is a remarkable variable star. This star undergoes a considerable change in its brightness. For in about 4 hours it gradually diminishes in lustre, from    between a second and third magnitude, till it appears as a fourth magnitude    star; it

remains as such    for about    8 minutes, and then in the    next 4 hours recovers its brightness in a like gradual manner,

and retains it for the remaining part of its period—viz., 2 days, i2-| hours. The period in which all these variations are performed is 2 days, 20 hours, 49 minutes.]

Above Perseus is Taurus, the Bull, the second constellation of the Zodiac; its principal star,    is

now due North, being exactly on the meridian; this star represents the eye of the Bull, and the stars and £ the two horns. The beautiful cluster of stars called the Pleiades, forms part of this constellation. It will be observed to the left of, and below the bright ruddy star, Aldebaran. Six stars are distinctly seen in this group, though more are visible with good eyesight. Fig. 8 is a view of this cluster as seen with a small    .


telescope. This celebrated group of stars is mentioned by Job; and Hesiod, who lived 2800 years ago, makes mention of it in one of his works in the following lines :—

“ There is a time when forty days they lie,

And forty nights, concealed from human eye,

But in the course of the revolving year,    ■    .

When the swain sharps the scythe, again appear.”

Near Aldebaran another group of stars, not so conspicuous as the Pleiades, will be noticed; this one is called the Hyades.

To the right of the North, and tipping the horizon, we now see the brilliant Capella, the “ Shepherd’s Star,” in Auriga, the Waggoner, one of the old asterisms.

The Arabs called Capella the “ Guardian of the Pleiades,” and it was sometimes considered as a separate constellation. To the right of Auriga is Gemini, the Twins, the conspicuous stars Castor (a) and Pollux (8)having just come into view. Above Taurus we see the noble Orion, now standing erect near to the meridian; while above Orion is Lepus, the Hare. Canis Major, the Great Dog, is now due East, and midway between the zenith and the horizon; its principal star,    , will be seen sparkling with great brilliancy.

Directly underneath the “Dog Star” (Sirius) is Procyon, the leading star in Canis Minor, the Little Dog.

Stretching from the North-East to the South-East will be observed the long constellation of Hydra, the Serpent; its most conspicuous star, Alphard, “ the Solitary One,” is now due East, near to the horizon. The Ship, Argo, has now moved between the East and the South-East, the bright star,    , now being South-East,

and at a high altitude. Observe the numerous branches and offshoots of the Milky Way as it passes through this constellation, especially its complete division by the dark gap lying between the stars a and <5. To the right of Canopus are the small constellations Dorado and Reticulum; while between the South and the South-East the conspicuous Cross, Crux, will be noticed, and part of the constellation of Centaurus.

The Pleiades. The legend tells that they were seven daughters of Atlas. The gods placed them among the stars, near their sisters the Hyades, all seven being visible to men, until Sterope faded away, shamed that she alone of the sisters had condescended to marry a mortal. The ‘fading’ legend is doubtless based on astronomical fact.

Perseus. The old Greek legend tells that Perseus was the son of Zeus (Jupiter) and Danae. The goddess Athene sent him to slay the Gorgon Medusa, procuring for him Mercury’s winged sandals to speed him on his way. After many adventures Perseus found the Gorgon’s den, and mindful that whoever looked on Medusa would be turned to stone, used his shield as a mirror when he cut off her head with Athene’s magic sword. On his way back, he chanced on the fair maiden Andromeda, chained to a rock as a victim to Neptune, and when a sea monster came to devour her, he turned it to stone by displaying the Gorgon’s head. Perseus married

Andromeda, and after they were dead they were placed close together among the stars, beside Andromeda’s parents.

¿22

Map 3. THE CONSTELLATIONS FOR DECEMBER AND JANUARY.

HJ-OOS

WEST



EAST


NORTH

Map 3. THE STARS VISIBLE AT THE FOLLOWING DATES & HOURS (Rt. Ascension 4 hrs. on Meridian)

Nov.

21,

12*0

Dec.

6,

11*0

Dec.

21,

10*0

Jan.

5,

9*0

Jan.

20,

8*0

Feb.

5,

7*0

26,

11*40

,,

11,

10*40

99

26,

9*40

99

10,

8*40

99

25,

7*40

99

10,

6*40

Dec.

1,

11*20

99

16,

10*20

99

31,

9*20

99

15,

8*20

99

30,

7*20

99

15,

6*20


Date p.m.    Date    p.m. Date    p.m. Date    p.m. Date    p.m. Date    p.m. Date p.m.

Feb. 20, 6*0 „    27,    5-30

Mar. 7, 5*0

AFTER MIDNIGHT. Nov. 14,12-30a.m.; Nov.6,1 a.m.; Oct.21,2a.m.; Oct.6,3a.m.; Sept.21,4a.m.; Sept. 14,430a.m.; Sept. 6,5a.m.

C %U!13

WEST


Map 4. The Constellations for January and February.

Hinos



NORTH


Map 4. THE STARS VISIBLE AT THE FOLLOWING DATES & HOURS (Rt. Ascension 6 hrs. on Meridian):

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Dec. 21,

12*0

Jan. 5,

11*0

Jan.

20,

10*0

Feb.

5,

9*0

Feb.

20,

8*0

Mar.

7,

12,

7*0

Mar. 22,

6*0

,, 26,

11*40

n 10*

10*40

W

25,

9*40

»

10,

8*40

**

25,

7*40

»

6*40

,, 29,

5*30

» 31,

11*20

** 15»

10*20

W

30,

9*20

»

15,

8*20

Mar.

2,

7*20

w

17,

6*20

Apr. 6,

5*0

AFTER MIDNIGHT. Dec. 14, i2,3oa.m.; Dec. 6, i a.m.; Nov. 21, 2 a.m.; Nov. 6,3 a.m.; Oct. 21, 4 a.m.; Oct. 14, 4 30a.m.; Oct. 6,5 a.m.


N the South, and near the horizon, will be seen the constellations Ara, Triangulum, and Pavo; above which is Hydrus and Toucan. Grus, the Crane, is now in the South-West, setting; while above Grus is Phoenix. Between Phoenix and Toucan will be noticed the brilliant star, Ache mar, in the River Eridanus—“ Orion’s River,” which constellation will be seen twisting towards the North-West. Below Eridanus, and near the Western horizon, is the extensive constellation of the Whale, Cetus; with Pisces underneath, and nearly set. Aries, the Ram, is in the North-West, close to the horizon; to the right of it is Perseus, all but disappeared. Above Perseus is Taurus, with its beautiful group of stars, the Pleiades, and its bright red star, Aldebaran («). From this star being so very red, and lying near the paths of the planets, it has often been mistaken by inexperienced observers for the ruddy planet Mars. Directly underneath the horns of the Bull (£ and (3 Tauri), and just tipping the horizon, is Auriga, with its leading brilliant,    , scintillating brightly.


To the West of the meridian, and midway between the zenith and the horizon, we see Orion, now at his greatest elevation—the best position to be well observed. This is the most beautiful and brilliant of all the constellations, and in ancient times there was none more noted than Orion, the “ Mighty Giant.” Manilius, the astronomical poet of the ancients, thus writes about Orion :—

His isles of light, his silvery streams, And gloomy gulfs of mystic shade.”


“ Orion’s beams ! Orion’s beams !

His star-gemmed belt, and shining blade ;

%

The three stars in a line near the centre of the group, are called the “ Belt,” and by Job the “ Bands of Orion; ” they are known, however, by many other names, such as the “Three Kings,” the “Ell-and-Yard,” “Jacob’s Staff,” &c. The star a in this constellation is called Betelgeux; it is a very irregular variable star, and forms with Procyon and Sirius a large equilateral triangle. Directly above the middle star in the belt, there will be seen a star surrounded with a haze; this is the great Nebula of Orion, one of the most wonderful objects in the heavens. A very small telescope will suffice to show it as a luminous cloud with small stars shining through it; but it requires one of those monster telescopes which astronomers now use to see it to advantage. When seen with one of these instruments, it is truly a magnificent and wonderful sight; the whole field of view is filled with an irregular mass of green shining mist, which is apparently broken up into flocculent masses, delicate clouds of light, sprays, and wisps, and standing out from the cloudy background, like a sprinkling of diamond dust, are seen faint glittering stars. The real nature of this mysterious object long remained unknown, for telescopes without number have been turned to it in the hope of resolving its misty light into stars, but each have failed in turn. Even the 40 feet reflector of Sir W. Herschel, which was 4 feet in diameter, could not reveal the individual stars that were supposed to produce this luminous haze. Nay, even the gigantic reflecting telescope of Lord Rosse, with its 6 feet mirror, could not resolve it completely. Astronomers, therefore, were rather taken by surprise when Mr. Huggins announced that, by means of the spectroscope, it was demonstrated that this object was nothing more than incandescent gas, such as hydrogen, nitrogen, &c. Observations show that this magnificent object is about 2000 light-years distant from the Earth.

Above Orion is Lepus, and nearly overhead is Columba. Canis Major, with its “blazing dog star,” Sirius, is to the right of these constellations; while below Sirius is the bright star, Procyon, in Canis Minor. Between the North and the North-East we now see Gemini, the Twins, and Cancer, the Crab, both Zodiacal constellations. The latter constellation contains no conspicuous stars, but it has a noted star cluster, which is called the “ Beehive ”—the “ Praesepe ” of the ancients. This small group is very easily found, for a line from    -the


uppermost of the two brilliant stars in the Twins—to R(in Leo) will, about midway between these stars (see present map) pass very near to it. When this cluster of stars is seen with a telescope, it is a magnificent sight, each sparkling like so many' diamond points against the dark sky. Fig. 9 is a view of this interesting cluster as seen with a telescope.

Leo, the Lion, has now partly risen into view; its principal star, Regulus, the “ Lion’s Heart,” being well above the horizon. In the East, Crater, the Cup, 'and Corvus, the Crow, have also appeared; while the Sea Serpent, Hydra, has risen considerably higher in the heavens. Argo is rapidly approaching the zenith, its leading star,    , having already

reached its highest altitude; between this conspicuous star and the bright star, Achernar (a) Eridani), will be seen Dorado and Reticulum; and Crux and Centaurus below Argo.    Fig. 9. The Prxsepe,

The ‘Heavenly Twins,’ Castor and Pollux, brothers of Helen of Troy, were placed among the stars by Jupiter to reward their constancy to one another. Roman legend tells how, at the battle of Lake Regillus, when the hard-pressed Roman general vowed a temple to the Twins, they suddenly appeared on milk-white horses to aid him; and how, unaware, at first, who had come to his help, he sought them in vain after the victory.

C *4118    ^

Description of Map V.


HE Peacock, Pavo, is now due South and close to the horizon; to the right of it we see Toucan, above which is Hydrus, the Water Snake, with Nebecula Major and Minor, the Magellanic Clouds, above and below it. The brilliant star, Achernar (a Eridani), has fallen much lower in the heavens, and has now passed the South-West; while the straggling constellation of the River, to which this star belongs, will be observed winding nearly to the North-West. Underneath Achernar, Phoenix will be seen, a little above the South-West horizon; while above Achernar, are the constellations Reticulum and Dorado, and higher still is the brilliant Canopus, in the ship, Argo, which is now directly overhead.

Looking due West, we see that Cetus is about to disappear, part of this constellation having already set. North-West we see Taurus, now rapidly approaching the horizon, Above the principal star in the Bull, Aldebaran, is the noble constellation of Orion; and above Orion is Canis Major, at a very high altitude.


The leading star in Canis Major, Sirius, is the brightest star in the heavens; it will be seen midway between the zenith and Betelgeuse (a) in Orion (see note below). Early measurements of the distance of Sirius made it six times the distance of the nearest star, and Fig. io shows its (then) supposed size compared with the Sun; now, however, it is known to be only twice the distance of the nearest star, and about twice the size of the Sun—also twice as hot, having a surface temperature of 2o,ooo0 F. Placed at the same distance as the Sun, it would be 26 times more luminous. Unlikely as it may seem, there is an intimate connection between this southern star and the principal stars of far-north Ursa Major, for they are all members of a star group travelling at the same speed towards the same point on the star sphere. From minute irregularities in the motion of Sirius, it was certain that some unseen body must be affecting it. This was at last discovered, but it was so very faint that it was thought to shine by reflected light only. Astronomers got a great surprise when, at last, it was found to be really a very luminous star, and that its faintness was due to its excessively small diameter (for a star) only about the size of Uranus: further, that its density was almost incredible, 50,000 times that of water, so that a cubic inch of it would weigh f ton !

To the left of Canis Major, Columba, the Dove, will be noticed; it is a modern constellation. Lepus, the Hare, is between Columba and Orion; and a little to the west of the meridian, underneath Sirius, is Canis Minor, the Little Dog, with its conspicuous star Procyon—which means ‘ Before the Dog ’—so named because in the Northern Hemisphere it rises before Sirius, the Dog Star, and thus heralds its appearing. Procyon has one of those remarkable dense companions known as ‘White Dwarfs,’ its mass being of some four tons per cubic inch, and one star is known with its atoms so closely packed that each cubic inch weighs 620 tons ! Before actual discovery, these unseen, but well-authenticated bodies were at one time supposed to be quite dark, and for all we know, there may be vast quantities of such dark bodies scattered through space. For a long time, the partial eclipses of Algol, in the constellation of Perseus, were attributed to such a dark body, but we know now that Algol’s system consists of three stars; each of these emits light, but of different intensity, so that when the fainter stars come partially between us and the brightest star, the light is decreased.

Directly under Canis Minor is the third constellation of the Zodiac, Gemini, the Twins—originally represented as a pair of kids, but the Greeks altered them into two children, Castor and Pollux (see p. 23). To the right of Gemini is Cancer, the Crab, the faintest of the Zodiacal constellations; its brightest star is 4th magnitude. In the north-east we now see Leo, the Lion, with its ‘Sickle group’ (upside down in this hemisphere), formed by the stars a, 17, y, £,    p, and e—a ( Regulus, the brightest star) and y forming the handle. Above the Lion, Hydra,

the Sea Serpent, will be seen, with its principal star Alphard (a)—directly above Regulus—at the end of a graceful curve of small stars stretching towards the horizon. In the East we now see the Virgin, Virgo, coming into yiew, its leading brilliant Spica (a), being perfectly clear of the horizon. Above Virgo, are the interesting constellations Corvus and Crater, both old asterisms. Crux and Centaurus have now reached the South-east, and have attained a fair altitude above the horizon. Under the Centaur, will be noticed the small constellation of Lupus, the Wolf; while to the right of Lupus, and between the South-east and South, are Ara, the Altar, and Triangulum.

Betelgeuse is one of the reddest of the bright stars. Its diameter appears to be about 300,000,000 miles, large enough to include the whole orbit of the Earth. Despite its enormous size, it has a density of only one-millionth that of water, or one-thousandth that of air. It varies very slightly in brightness over half a magnitude, and it is thought that its diameter varies in relationship to its brightness, from the different measurements that

have been obtained at different times.

S24

Map 5. The Constellations for February and March.


north

Map S. THE STARS VISIBLE AT THE FOLLOWING DATES & HOURS (Rt. Ascension 8 hrs. on Meridian)

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Jan.

20,

12*0

Feb. 5,

11-0

Feb. 20,

10-0

Mar.

7,

9-0

Mar. 22,

8-0

Apr.

6,

7-0

Apr.

21,

6-0

25,

11-40

» 10,

10-40

,, 25,

9-40

»

12,

8-40

„ 27,

7-40

n

11,

6-40

28,

5-30

»

30,

11-20

i ,, 15,

10-20

Mar. 2,

9-20

»

17,

8-20

Apr. 1,

7-20

»

16,

6-20

May

7,

5-0

AFTER MIDNIGHT. Jan. 13,12-30 a.m.; Jan. 5,1 a.m.; Dec. 21, 2a.m.; Dec. 6,3 a.m.; Nov. 21, 4 a.m.; Nov. 14, 4 30a.m.; Nov. 6,5 a.m.

C5 3118

Map 6. The Constellations for March and April.

Hinos


EAST


NORTH


Feb.


Map 6. THE STARS VISIBLE AT THE FOLLOWING DATES & HOURS (Rt. Ascension 10 hrs. on Meridian)

Date p.m.    Date pm. Date pm. Date    p.m. Date    p.m. Date p.m. Date p.m.

20,

,,    25,

Mar. 2,    11*20

12*0

11*40

Date

pm.

Date

p m.

Date

p.m.

Date

p.m.

Date

p.m.

Mar. 7,

,, 12)

11*0

Mar. 22,

10*0

Apr.

6,

9*0

Apr.

21,

8*0

May

7,

12,

7*0

10*40

„ 27,

9*40

»

11,

8*40

«

26,

7*40

»

6*40

„ 17,

10*20

Apr. 1,

9*20

16,

8*20

May

1,

7-20

»

17,

6*20

May 22, 6*0 „    29,    5*30

June 6, 5*0

AFTER MIDNIGHT. Feb. 13, 1230 a.m.; Feb.5, i a.m.; Jan.20, 2a.m.; Jan. 5,3a.m.; Dec.21, 4a.m.; Dec. 14, 4-30a.n1.; Dec.6,5a.m.


OUCAN and Hydrus have now moved nearly to the South; while the principal star in the River, Achernar,will be seen to the right of these constellations, between the South and the South-West. Eridanus is now beginning to disappear, part of it having already set. In the South-West, and above “ Orion’s River,” will be noticed the small groups Reticulum and Dorado; above which is the brilliant star, Canopus, in the Ship, Argo, which has now moved from overhead towards the South-West. [This constellation is supposed to represent the famous ship in which Jason and the daring Argonauts sailed to Colchis, to recover the Golden Fleece, which Phryxus had taken to King ZEtes. • Jason, favoured by Juno, accomplished the voyage after passing through great dangers, and successfully brought back the fleece. According to the story, on one occasion the Ship had to sail through a very dangerous passage, which was closed by certain rocks, called “ Symplegades,” or dashers, which floated on the surface of the water, and closed together so suddenly, when anything attempted to pass, that even birds could not escape. Phineus advised the Argonauts to send a dove through the Symplegades, and if it was successful in escaping, then to make the attempt. They did this, and the dove lost its tail in the passage. This encouraged the Argonauts to risk the trial, which was successfully carried out, for the Argo, assisted by Juno, and impelled by the heroic efforts of its brave crew, sailed so swiftly between the dreaded rocks that it escaped, with a loss of only some of its stern ornaments. But though this constellation may have been connected afterwards with the famous Argonautic Expedition, yet it is thought that it is even of an older date; some consider that this constellation of the Ship originally represented Noah’s Ark (see page 4)].


In the West we now see Orion rapidly approaching the horizon. To the left of this noble constellation is Lepus, the Elare, one of the animals which Orion hunted. Above Lepus is Canis Major, with its “ blazing Dog Star,”    Sinus;while to the left of the Great Dog will be noticed Columba. Taurus has now completely

disappeared; and in the North-West, Gemini is rapidly setting. Above the Twins is Procyon (a) in Canis Minor, one of Orion’s Hounds; to the right of which, and nearer the horizon, is the barren constellation of Cancer, the Crab. Due North, and just above the horizon, we see the only part of Ursa Major, the Great Bear, which is ever visible in our latitudes: the stars belonging to this constellation, which are now seen, represent the paws of the Bear (see Plate A). The fifth Zodiacal constellation, Leo, is now on the meridian, its leading star Peg ulus, the Lion’s Heart, being a little to the left of the North. Below Regulus, and midway between the stars y and s there is situated the radiant point of the famous 13th of November meteor system, or that point in the heavens from which

these meteors appear to burst (see page 13), and on which account these shooting stars are familiarly known as Leonides.


1 he long faint constellation of Hydra will now be observed high in the heavens, stretching from the East nearly to the North-West. This is one of the old constellations, its principal star is called Alphard, the “solitary one,” it will be seen between the North and the North-West, at the apex of a large triangle, whose base is formed by the stars Procyon (a Canis Minoris), and Regulus. More than four thousand years ago this constellation of the Sea Serpent coincided with the Equinoctial (fig. 11), but, owing to the swaying motion of the axis of the earth, the Equinoctial has since moved away to its present position among the stars, which will be seen in the Fig. In the North-East we see Virgo, with its conspicuous star, Spica, now risen perfectly clear of the horizon; while to the left, and below this constellation, the faint and scattered group of stars, Coma Bernices, will be observed. Above the Virgin are the two small constellations Corvus and Crater, both very old asterisms. These constellations are said to be con-    Ir* Hie Equator 4000 years ago.

nected with the story of the Deluge—Corvus representing the raven which was sent out of the Ark, and Crater, the cup which caused the patriarch of old to fall into sin, but this view is now considered most improbable.

Nearly North-East we see Bootes, the Herdsman, beginning to appear, its brightest star, Ardurus, being near the horizon, and directly underneath Vindematrix, s Virginis. Scorpio, and Ophiuchus, are also beginning to appear for the season; they will be seen due East, close to the horizon. Above these constellations is Libra, the Balance; while to the right of Libra is the conspicuous constellation of Scorpio, the Scorpion, with its brilliant fiery red star, Antares. Centaurus is now midway between the horizon and the point overhead, with Crux above, and Lepus, the Wolf, underneath ; while to the right of Centaurus, and near to the South, the constellations Ara, Pavo, and Triangulum, will be observed.

New Star in Pictor. In 1925, a new star appeared near a of the faint constellation Pictor (Plate Q— roughly, halfway between Canopus and the Greater Magellanic Cloud—at some distance from the Milky Way, unlike most of the other new stars, or ‘Novae,’ as they are called. It attained magnitude if before fading away.

.    S2K

OUCAN is now to the left of the South; Hydrus being above and to the right.    is



now at its lowest, and nearly South. To the right of this bright star, and stretching along the horizon beyond the South-West, will be seen the only part of the River, Eridanus, which is now visible, the greater part of it having already set. Above the

River is Reticulum and Dorado; while above and to the West

* »

of Dorado is the Ship Argo. This constellation contains a very remarkable variable star called q (Eta), its position in the heavens will be seen by referring to Fig. 12. This star undergoes the most extraordinary variations in its brightness during the course of about half-a-century. At one time it is so very famt as to be invisible to the naked eye; at another it shines only as a fifth magnitude star, it then increases its light till it reaches the brightness of a second magnitude star, and sometimes it has actually been seen to surpass stars of the first magnitude, and even to approach the brilliancy of Sirius. The rapidity with which these changes sometimes take place, the irregularity of their periods, the extent of the variations, and the want of some known law to explain these phenomena, all combine to make this star one of the most interesting objects in the heavens.

In the West we now see Canis Major, with its conspicuous star, Sirius, sparkling brilliantly. To the left of Sirius, is Columba, Noah’s Dove, a modern constellation, being named by Royer in 1769; while underneath the Great Dog is Lepus, nearly set. Between the West and the North-West is Procyon, in Canis Minor, rapidly approaching the horizon; to the left of which, and nearly North-West, is Cancer, the Crab. Above Cancer, and twisting upwards past the zenith, will be seen the faint stream of stars forming the constellation of Hydra, the Sea Serpent; its principal star, Alphard(a), now being above and a little to the right of Procyon. Leo is now between the North and the North-West; with Leo Minor, the Little Lion, and part of Ursa Major, the Great Bear, underneath. Corvus and Crater are now due North, and nearly overhead. Below Corvus is the sixth Zodiacal constellation Virgo, the Virgin, which contains a very conspicuous star, called    Underneath Virgo is Coma

Berenicis, the Hair of Berenice. This constellation was named by Tycho Brahe about 1603; it originally belonged to Leo, its faint cluster of stars forming the tuft of hair in the tail of the lion. Due North, and near the horizon, the star Cor Caroli will be observed, the principal star in the small, modern constellation of Canes Venatici, the Greyhounds.

Between the North and the North-East the noted constellation of Bootes, the Herdsman, will be observed,, with its brilliant star, Arcturus. To the right of Bootes, and just above the horizon is Corona, the Crown. Hercules is now beginning to appear between the North-East and the East; above it Serpens, the Serpent, will be observed, winding through Ophiuchus, the Serpent-Bearer, nearly to the eastern horizon. Above Serpens, and a little to the left of the East, is Libra, the Balance; while to the right of Libra is Scorpio, the Scorpion, with its bright, fiery, red star, Antares.Sagittarius, the Archer, is underneath Scorpio, and between the East and the North-East; and above Scorpio are the conspicuous constellations Crux, the Cross, and Centaurus, the Centaur. The Cross is a modern constellation, it having belonged at one time to Centaurus. The principal star (a) in the Centaur is celebrated as being the nearest star to our solar system, as at present known. The distance of this star has been found from its annual parallax—that is, the angular displacement of a star as viewed from opposite sides of the earth’s orbit. This angular displacement is so small that it is only by means of the most delicate instruments that astronomers have been able to detect it. This extremely small angle, is about the same as the angle one shilling would give, as seen from the distance of nearly three miles. It is from this small angle that the distance of a Centauri has been calculated to be nearly three hundred thousand times greater than the sun, or twenty-eight billion miles. This distance is so great that light, which travels over twelve millions of miles in a minute, requires no less than four and a-half years to journey from it to us. If, then, this is the distance of the nearest star, how vast must be the distances of those stars which, from their remoteness, can only be but momentarily seen in the most powerful telescope now possessed by astronomers; for their light must have taken at least tens of thousands of years to reach the earth. Below a Centauri is Triangulum, and Ara; beneath them, Pavo and Indus.

The Nearest Star. A faint star which is thought to revolve round a Centauri—known as Proxima Centauri —is a little nearer    light-year) than that star, being on the Earthward portion of its orbit. The parallax of a Cen

tauri, as first found, was 1"; modern measures make it f" = 270,000 times the distance of the Sun, or 4^ light years.

Antares. The diameter of this ‘Giant’ star subtends an angle of 44/iooths of a second, which at the star’s supposed distance gives a diameter of some 400 million miles—about 450 times that of the Sun, though it may be less.

WEST


Map 7. The Constellations for April and May.

H±nos


EAST


* NORTH

Map 7. THE STARS VISIBLE AT THE FOLLOWING DATES & HOURS (Rt. Ascension 12 hrs. on Meridian)

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Mar. 22,

12*0

April 6,

11*0

April 21,

»,26»

10*0

May 7,

9*0

May 22,

8*0

June

6,

7*0

June 21,

6*0

» 27?

11*40

» 11,

10*40

9*40

>» 12,

8*40

„ 27,

7*40

W

11,

6*40

,, 28,

5*30

April 1,

11*20

w

10*20

May 2,

9*20

„ 17,

8*20

June 1,

7*20

W

16,

6*20

July 7,

5*0

AFTER MIDNIGHT. Mar.15, 12*30 a.m.; Mar.7, i a.m.; Feb.20,2a.m.; Feb.5, 3a.m.; Jan.20, 4a.m.; Jan. 13,4*30 a.m.; Jan.5,5a.m.

WEST


Map 8. The Constellations for May and June.

H±DOS


EAST


NORTH

Map 8. THE STARS VISIBLE AT THE FOLLOWING DATES & HOURS (Rt. Ascension 14 hrs. on Meridian):

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Apr.

21,

26,

12-0

May

7,

12,

11*0

May 22,

10*0

June

6,

9*0

June 21,

8*0

July

7,

12,

7*0

July 22,

6*0

11*40

«

10*40

w 27,

9*40

»

11,

8*40

,, 26,

7*40

w

6*40

,, 29,

5*30

May

2,

11*20

17,

10*20

June 1,

9*20

w

16,

8*20

July 1,

7*20

w

17,

6*20

Aug. 6,

8*0

AFTER MIDNIGHT. Apr. 14,12-30a.m.; Apr.6, ia.m.; Mar.22, aa.m.; Mar.7,3 a.m.; Feb.20,4a.m.; Feb.13,430 a.m.; Feb.5,5a.m,

The circular boundary of the Map is the Horizon, with the principal points of the compass indicated: The Gross in the centre is the Zenith—that part of the sky which is directly overhead.

Notes on using this map, and star names corresponding to the Greek letters, see p. 18.

YDRUS is in the South but near the horizon. Centaurus is now nearly overhead, with Crux beneath and to the right. The whole of Eridanus has now disappeared, with the exception of its principal star, Achernar, which will be seen low down on the horizon, and a little to the left of the South. To the right of Hydras are the constellations Reticulum and Dorado. The Ship, Argo, has now reached the South-West, and underneath it will be seen the only portion of Canis Major now visible— Sirius having already set.



In the West we see Hydra, the Sea Serpent, twisting upwards near to the zenith. Corvus and Crater are to the right of Hydra, and between the West and the North-West; while above Leo is Virgo—its bright star, Spicci, having now passed the meridian at a high altitude. Underneath Virgo is Coma Berenices—this constellation contains many clusters of small stars and nebuhe; it was formerly part of Leo. Below Coma Berenices, and just above the Northern horizon, will be noticed the star Benetnasch, (g) in Ursa Major, the Great Bear. Bootes, the Herdsman, has now moved much nearer to the North; its principal star, Arcturus, being on the meridian and at a fair altitude. To the right of Bootes is Corona Borealis, the Northern Crown. The brightest star in it is called Alphecca, which will be seen sparkling like a gem in this “celestial coronet.” To the right of Alpecca, and in a position where no star was visible to the naked eye, there appeared very suddenly in the year 1866 a new star, shining with great brilliancy, and which in due course rapidly disappeared again ; the true position of this star will be seen in Fig. 13. It was known as the “ Blaze Star,” rising suddenly to the 2nd magnitude. Nine days later it became invisible to the naked eye, and after a few weeks reached the 9th magnitude. Later, it increased to the 7th mag., and then fell to mag. 9^, its present brightness. Some tremendous disturbance had taken place on this star, caused, probably, by the sudden disruption of some mighty mass of matter, which had the effect of making it shine out with about nine hundred times its former brilliancy ! It might be of interest to consider what would likely be the result if a conflagration like that which undoubtedly took place on this remote sun, were at any time to happen to our sun ? Would any of the life on earth ever hope to survive such an awful change in heat and light as this ? No, for not only would all the various forms of life on earth be utterly destroyed, but on all the other members of our solar system there would be such a change effected, that if any life existed, even on the remote Pluto, it would at once be completely extinguished.

To the right of the Northern Crown is the old constellation of Hercules, which is supposed to represent a man kneeling; its principal star, which is not a very conspicuous one, will be seen North-East. To the right of this star is Has Alhague (a) in Ophiuchus, the Serpent-Bearer. Above Hercules, and winding through Ophiuchus, is Serpens, the Serpent. Above the Serpent’s head, formed by the stars ¡3 and y, is Libra, the Balance. Aquila and Capricornus are now beginning to appear in the East. Above these constellations is Sagittarius, and above the Archer is the conspicuous constellation of Scorpio; its leading star, the bright, red Anlares, having now attained a considerable altitude above the horizon, between the North-East and the East.

To the right of Scorpio is Ara, which is said to represent the altar on which Noah offered a sacrifice after leaving the xArk. Between Ara and Centaurus is Triangulum, while underneath the Triangle is Pavo, to the left of which is Indus. Below Indus and South-East is Grus, the Crane; while to the right of Grus is Toucan.

Novae. Sometimes a faint star will rise suddenly to great brilliance, endure for a time, and then fade away to its original brightness, or even less, with perhaps small fluctuations at irregular intervals. Various theories have been advanced as to the cause of their apparition. As indicated above, some think it is due to the explosion or disruption of matter in a star. Others look for it in the collision of a star with some other body, or its encounter with a cloud of nebulous matter.

Very seldom do bright Novae occur like this one in Corona Borealis. Less than a dozen, visible to the naked eye, have appeared since the beginning of this century, but many, whose maximum brightness may be only magnitude 13, are discovered annually by the telescope or spectroscope. These usually are found in nebulae.

Hercules was a grandson of Perseus, and was promised immortality if he performed ten apparently impossible tasks. These “labours of Hercules” led him to many far-off lands, and into many adventures; but his immense strength enabled him to complete them successfully. Later, having unwittingly put on a poisonous garment, he suffered such torture that he ascended a funeral pile, and had it set on fire. But, says the legend* the gods descended, and carried him up to heaven.

ENTAURUS has now fallen away from overhead; Crux being underneath and now South-West Argo is below Crux; its principal star, Canopus, will be seen low down on the horizon, between the South and the South-West. Lupus, the Wolf, is above the Centaur and nearly overhead. In the West, we now see Hydra setting, its leading star, Alphard, having already disappeared. Crater and Corvus are to the right of Hydra—Corvus being directly above Crater. Virgo, the Virgin, with its conspicuous star, Spica, is now nearing the horizon; underneath it we see the only part of Leo which is at present visible.


Nearly North-West and close to the horizon is Coma Berenices; to the right of which Bootes, the Herdsman, will be seen with its brilliant star, Arcturus. [This star is travelling through space at an almost inconceivable speed, in fact its apparent motion is so great that since the beginning of our era, it has changed its position in the heavens by two and a-half times the apparent diameter of the moon. Owing to this star having so great an apparent movement (called by astronomers “ proper motion ”) it was long supposed that it was one of the nearest stars; but now it has been found that it is situated at a distance not less than seven times that of the nearest known star ; so that its light will require at least twenty-five years to reach the earth. According to Mr. Huggins it is travelling towards us at the enormous velocity of over fifty miles per second. The heating effect, too, of this star has been measured, it being found by Mr. Stone that we receive as much heat from Arcturus, as would be given out by a three inch cube of boiling water placed at a distance of four hundred yards.]

To the right of Bootes is Corona Borealis, above which is Serpens, twisting through Ophiuchus to the NorthEast. Below Ophiuchus, and Serpens, is Hercules, now nearly North. The constellation of Lyra, the Harp, has now risen into view; its brightest star, Vega, will be seen just above the horizon, between the North and the North-East. Libra, the Balance, is above Serpens; while the conspicuous constellation of the Scorpion, Scorpio, is now nearly overhead, its beautiful red star, Antares, being a little to the North of the zenith. The Milky Way is particularly worth observing, as it traverses this constellation; here, it is very brilliant and irregular. This luminous zone is also very conspicuous near the Cross; at which constellation there will be observed a large and very dark opening. This opening has been called the “Coal Sack” from its intense blackness in contrast with the surrounding luminosity. This is, actually, a cloud of non-luminous matter—a dark nebula.

Between the East and the North-East, the constellations Aquila, Delphinus, and Equuleus have now appeared. In the East we see Capricornus, the Goat, with part of Aquarius, the Water-Bearer underneath; and above the Goat, is Sagittarius, the Archer,—all of these being Zodiacal constellations. Above the South-Eastern horizon the bright star, Fomalhaut,will be observed, which is the principal star in Piscis, the Fish. Grus is above Piscis, while above Grus are the constellations Indus and Pavo. Triangulum, the Triangle, is now due South, and at a considerable altitude; above and to the left of it will be seen Ara, the Altar. Achernar (a) in the River, Eridanus, is now beginning to rise in the heavens; above it is Toucan and Hydrus; while below and to the right of Hydrus, are the small constellations, Reticulum, and Dorado.

The Milky Way. The irregularities, now seen at their best, are supposed to be largely due to clouds of non-luminous matter intervening between us and the faint stars of the Milky Way beyond—which is believed to form a complete circle in- reality. Photography reveals such opaque clouds in different parts of the sky. From peculiarities in the light of some stars, also, there is some reason to believe that a cloud of calcium vapour intervenes between them and us, which, though unseen by telescope or camera, has left its indelible earmark on the star’s light during its passage, as revealed by the spectroscope. It has been found, also, that the stars tend to move in two streams in opposite directions, towards points in the Milky Way; one between Betelgeux and y of Gemini, comprising some 60% of the stars, the other between rj of Serpens and X of Sagittarius, comprising 40%.

Arcturus. Recent measures make it ten times more distant than the nearest star, or 43 light-years. Its diameter is 25 times that of the Sun, or 21 million miles; and it is 140 times more luminous, but some 3000° Fahr. cooler, being an early ‘Giant’ star. We receive from it as much heat as from a candle 8 miles away.

“Arcturus” is twice mentioned in the Book of Job (Authorised Version), but in the R.V. it has been altered to “ The Bear ” in each case, following the general consensus of ancient translators. An Italian astronomer, however, points out that the Hebrew word translated “Arcturus” in one of the passages, is the same as that for “moth,” also that the characteristic < shape of the Hyades is exactly that of a moth with folded wings: he therefore makes the plausible suggestion that Job ix. 9 refers to the moth-shaped Hyades cluster, as would be natural when mentioning the Pleiades, and Job xxxviii. 32 to its brightest star Aldebaran, with his lesser companions in the cluster.

The Magellanic Clouds, so called in honour of the great navigator, are now low down in the south. They are situated at enormous distances—some 101,000 and 112,000 light-years, and are separate universes.

Vega, see page 30. New Star in Aquila, see page 29. Antares, see page 26.

¿28

WEST


Map 9. The Constellations for June and July

Hinos


EAST


NORTH


May 22,

12*0

June

6,

11*0

June 21, ,, 26,

10*0

July

%

9*0

July 22,

8*0

Aug.

6,

7*0

n 27,

11*40

11,

10*40

9*40

»

12,

8*40

„ 27,

7*40

»

11,

6*40

June 1,

11*20

w

16,

10*20

July 1,

9*20

»

17,

8*20

Aug. 1,

7*20

»

16,

6*20


Mar 10. The Constellations for July and August.

H1D0S


EAST


NORTH


Map 10. THE STARS VISIBLE AT THE FOLLOWING DATES & HOURS (Rt. Ascension 18 hrs. on Meridian)

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

June 21,

12*0

July

7,

12,

11*0

July 22,

10*0

Aug.

6,

9*0

Aug.

21,

8*0

Sept.

6,

7*0

Sept. 21,

6*0

,, 26,

11*40

w

10*40

« 27,

9*40

»

11,

8*40

26,

7*40

W

11,

6*40

m 28,

5*30

July 1,

11*20

17,

10*20

Aug. 1,

9*20

16,

8*20

»

31,

7*20

w

16,

6*20

Oct. 6,

5*0

AFTER MIDNIGHT. June 14,12 30 a.m.; June6,1 a.m.; May 22, 2 a.m.; May 7,3 a.m.; Apr. 21,4 a.m.; Apr. 14, 4 30 a.m.; Apr.6,5 a.m.

ANOPUS, the principal star in the Ship, Argo, is now due South and close to the horizon. Above Argo is the conspicuous Cross, Crux, and Centaurus, the Centaur, now nearly South-West Triangulum is to the left of the Centaur, while Ara is above the Triangle. In the West, we see that Crater is no longer visible, and that Corvus is rapidly nearing the horizon. To the left of the Crow, part of Hydra will be seen, twisting upwards. Virgo is also disappearing, part of it having already set. Above the Virgin, and now midway between the horizon and the zenith, is Libra, the Balance, the seventh Zodiacal constellation; while above the Balance is Scorpio,, the Scorpion, also belonging to the zone of animals.



Bootes with its brilliant, Arciurus, has now moved to the North-West, and is rapidly setting. Corona is to-the right of it; while above the Crown is Serpens, the Serpent, and Ophiuchus, the Serpent-Bearer; both very old aster isms. The principal star in Ophiuchus (a) is called Ras Alhague, from an Arabian word meaning the Serpent-Bearer’s head. To the left of this star, the leading star (a) in Hercules will be observed—it is called Ras Algethi,. from the Arabian Ras-al-jathi, the Kneeler’s Head—the constellation of Hercules being supposed to represent a. kneeling man. [It is towards that part of the heavens which is occupied by this constellation, that astronomers have ascertained, from the movements of the stars, that the sun with his family of revolving planets is at present travelling (see Fig. 14). This movement of the sun through space is probably round some distant centre of attraction. Indeed the German astronomer,

Madler, was led to suppose that the beautiful cluster of stars, the Pleiades, was actually the centre round which our sun, as well as all the stars in the galaxy, was moving. But this is not now thought to be the case, as the evidence from which Madler arrived at this conclusion was not sufficient for the solution of this extremely difficult problem; and many centuries may yet require to have passed before science will possess any accurate knowledge regarding the position of the true centre round which our own sun, and his companion suns, the stars, revolve.]

Lyra, the Harp, with its brilliant, Vega, is now near the meridian. To the right of it we now see the Cross of Cygnus between the North and the North-East; while above Cygnus is. Aquila, the Eagle. Sagittarius, the Archer, is nearly overhead; while between this constellation and the Eastern horizon, Capricornus, the Goat, and Aquarius, the Water-Bearer, will be observed—all three being Zodiacal constellations. Pegasus, the Flying Horse, is now beginning to make its appearance for the season; the part of this constellation which is at present visible, will be noticed between the East and the North-East. Above “ Nimrod’s Steed,” as Pegasus is called, will be seen Equuleus, the Little Horse; to the left of which is Delphinus, the Dolphin.

Piscis, with its bright star, Fomalhaut (a), and Grus, the Crane, have now risen perfectly clear of the horizon, and will be seen between the East and the South-East. Below the Crane, and near the South-Eastern horizon, Phoenix will be observed ; to the left of which will be noted the brilliant star, Achernar, in the River, Eridanus. Above Eridanus is Toucan ; while above Toucan are the constellations, Pavo, the Peacock, and Indus, the Indian. The Water Snake, Hydrus, with Reticulum and Dorado underneath, have now moved to the left of the South.

New Star in Aquila. In 1918, a “new star”—the brightest that has yet appeared since Kepler's Star in

x6o4_flashed out west of Altair, in the Milky Way, halfway between S of Aquila and rj of Serpens. It rivalled

Sirius for some time, but soon faded away like other new stars, and is now barely visible in a three-inch telescope.

Various theories have been advanced to account for these sudden outbursts, a collision between two stars being the most obvious explanation. The chances of such an occurrence, however, are probably very remote, while spectroscopic peculiarities in their light are difficult to explain on this basis. Another theory is that a star rushing through space encounters a “ dark nebula;” the friction of its passage through the tenuous gas evolves so-much heat that there is a tremendous conflagration. Another theory suggests that two stars graze, resulting in the formation of a third star—but explanations are largely guesswork at present.

In 389 a.d., a great new star appeared near Altair, and it would be natural to suppose that the 1918 star was simply its re-appearance after a lapse of some 1500 years. A well-known astronomer, however, states that careful analysis of the old records show that it must have been a comet, not a star.

£> DH/6


The Sun’s Motion in Space. Recent researches confirm—on the whole—Sir W. Herschel’s conclusion that the Solar Apex, i.e.,the direction in which our Sun is travelling, is towards the star A of Hercules (see Fig. 14), but modify it to the region somewhere about one-third of the way from A^ega to S of Hercules. Thus the Sun is. recedino from the point diametrically opposite on the star sphere—just E. of a Columbae, between Canopus and Sirius,

DESCRIPTION OF SVSAP XL


N the South, and close to the horizon, we see the Ship, Argo; its leading brilliam, Canopus^ beins a little to the left of the meridian. The Cross, Crux, has now fallen much lower in the heavens ; above it we see the constellation of the Triangle, Triangulum. The Centaur is now South-West, and nearing the horizon ;its two conspicuous stars, and being directly above the Cross. Midway between Centaurus and the zenith, the Altar, Ara, will be observed, to the right of which is the conspicuous constellation of the Scorpion, with its brilliant red star, (a) Antares.

Now due West, and directly underneath the Scorpion’s head, is Libra, the Balance; while above Scorpio is Sagittarius, the Archer, which will now be observed to have moved away from overhead towards the West. Below the Archer is Ophiuchus, the Serpent-Bearer, with the Serpent, Serpens, Wasting through it till it reaches the horizon—the Serpent’s head now being between the West and the North-West.

The kneeling Hercules has reached the North-West, part of it having already set. The small but conspicuous constellation of Lyra, the Harp, will now be noticed midway between the North-West and the North, with its bright, sparkling star, Vega. This star is thought to be a sun of enormous bulk, and situated at a vast distance away from us; its light probably requiring no less than ■ eighteen or nineteen years to reach our earth. To the right of Lyra, and due North, is the constellation of the Swan, Cygnus, appearing as a large inverted cross —the star at the top of the cross ( a), and nearest the horizon, is called    , and the one at the bottom 3),

Albireo. This star is a beautiful coloured double star when seen with the telescope.


Many years ago, astronomers were startled by the sudden appearance of a conspicuous star to the right of Arided, in the Swan, in a place where no star had before been visible to the naked eye. This strange star was first noticed by Professor Schmidt, of Athens, on the 24th of November, 1876; it obtained the same brightness as a star of the third magnitude, and then gradually faded away, and disappeared, till it required a telescope to reveal it. The exact position where this star appeared will be seen in Fig. 15. In the same Fig. there will be seen a small star marked 61 (a double star); this is the noted 61 Cygni—the nearest known star to us in the Northern hemisphere. With regard to it, Webb, in his “ Celestial Objects,” says :—“These suns were the first of the host of heaven to reveal to Bessel, in 1838, the secret of their distance. This is, probably,

366,400 times that of the earth from the sun—itself 92,400,000 miles—a space so vast that the light, which reaches us from the sun in eight minutes, employs nearly six years to traverse it. . . . How vast must be the dimensions of this great Universe! What a temple for the Creator’s glory! ‘All the whole heavens are the Lord’s’—those heavens are crow'ded with millions of millions of stars; and of all that countless multitude, millions, probably, for one, are at a distance incalculably exceeding that of 61 Cygni !”

Above Cygnus is Aquila, the Eagle, its three principal stars, ¡3, and 7 (A/tair,    and

respectively), being now on the meridian, and midway between the zenith and the horizon. To the right of the Eagle, and above Cygnus, will be observed the small constellations, Equuleus and Delphinus. The Flying Horse, Pegasus, has now risen perfectly clear of the horizon; the diagonal of the “ Great Square,” formed by the stars Algenib (7 Pegasi) and Alpheratz (a Andromedse), being vertical. Between Pegasus and the zenith the . Zodiacal constellations Aquarius and Capricornus will be seen—Capricornus being nearly overhead.

In the East, the constellations Pisces, the Fishes, and Cetus, the Whale, are now beginning to appear for the season. The bright star, Fomalhaut, in Piscis, the Fish, has now attained a considerable altitude; it will be seen between Cetus and the zenith. Grus is to the right of Piscis; and Phcenix is underneath Grus. The River, Eridanus, is rising rapidly in the South-East; its leading star,    being to the right of Phcenix, and at a

fair altitude above the horizon. Indus in now nearly overhead; Pavo being to the South of it. Between this constellation of the Peacock and the bright star, Acher?iar, Toucan will be observed, with Hydrus underneath' while below the Water Snake are the small constellations Reticulum and Dorado.

Vega is 33 light-years away, by later measures; it is 100 times more luminous than the Sun, and its temperature is nearly double—some 18,000° Fahr. A candle, six miles away, sends us as much heat.

6l Cygni- Now believed to be 700,000 times more distant than the Sun, so that its light takes 11 years to reach us: some faint northern stars, rather nearer than 61 Cygni, are now known. The nearest star is Centauri(p. 26).

NeW' Star in Cygnus. In 1920 another new star appeared in Cygnus, straight across the Milky Way with respect to that of 1876, and about the same angular distance from Alpha; it attained the 2nd magnitude.

AW

Map 1t. The Constellations for August and September.

Hinos


EAST


NORTH

Map 11. THE STARS VISIBLE AT THE FOLLOWING DATES & HOURS (Rt. Ascension 20hrs. on Meridian)

Date p.m.    Date p.m. Date p.m. Date    p.m. Date    p.m. Date    p.m. Date p.m.

July 22,

12*0

Aug.

6,

11*0

Aug.

21,

10*0

Sept.

6,

9*0

Sept. 21,

8*0

Oct.

6,

7*0 1

» 27,

11*40

11

11,

10*40

11

26,

9*40

11

11,

8*40

,, 26,

7*40

11

11,

6*40

Aug. 1,

11*20

11

16,

10*20

11

31,

9*20

11

16,

8*20

Oct. 1,

7*20

11

16,

6*20


„    28, 5-30

Nov. 6, 5-0

AFTER MIDNIGHT. July 15,12-30a.m.; July7.1 a.m.; June21, 2 a.m.; June 6,3 a.m.; May 22,4a.m.; Mayl5,4 30 a.m.; May7,5a.m.

The circular boundary of the Map is the Horizon, with the principal points of the compass indicated * The Cross in the centre is the Zenith—that part of the sky which is directly overhead.

Notes on using this map, and star names corresponding to the Greek letters, see p. 18.

Map 12. The Constellations for September and October.

H-Lnos


EAST


NORTH

p.m.

11-0

10-40

10-20

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Date

p.m.

Sept. 21,

10-0

Oct.

6,

9-0

Oct.

21,

8-0

Nov.

6,

7-0

Nov.

21,

6-0

„ 26,

9-40

99

11,

8-40

99

26,

7-40

99

11,

6-40

99

28,

5-30

Oct. 1,

9-20

99

16,

8-20

99

31,

7-20

99

16,

6-20 1 Dec.

6,

5-0


Date

Sept. 6, 1116,


,,

,,


Date p.m.

Aug. 22, 12*0 „    27, 11-40

Sept. 1, 11-20

HE Cross, Crux, has now nearly reached its lowest in the heavens; it will be seen close to the horizon, between the South and South-West. To the right of the Cross is Centaurus, now partly below the horizon; while above the two conspicuous stars, a and in this constellation, is Triangulum. Directly above the Triangle is the Peacock, Pavo, with Indus above and to the right. Grus, the Crane, is now overhead; while a little to the North of this constellation the conspicuous star, Fomalhaut,a in Piscis, will be seen. The Altar, Ara, is now South-West, and above the Centaur. Scorpio is rapidly setting; it will be noticed to the right of Ara, between the South-West and the West.


we see that a considerable part of Serpens, and Ophiuchus has disappeared. Above these constellations Sagittarius will be observed—it is now midway between the horizon and the zenith; its principal star, e, is called Kaus Australis. Lyra, the Harp, has now reached the North-Western horizon; only the stars ¡3 and 7 are visible, the brilliant star, Vega, having already disappeared.

Lying along the horizon to the right of the Harp, the Cross of Cygnus will be observed; directly above it is Delphinus, the Dolphin, and Equuleus, the Little Horse. The constellation of the Eagle, Aquila, will be seen above    Albireo, the star ¡3 in the Swan, its bright star, Altair, lying betwixt the stars ¡3 and 7 of the same constellation.

Exactly midway between “Jove’s Eagle,” Aquila, and the zenith is the Zodiacal constellation of the Goat—its principal star (a) is called Secundi Gieda.

Aquarius, the Water-Bearer, is to the right of Capricornus, and now on the meridian at a high altitude; its leading star is called Sadalmelik, from Sa’d-al-melik, “ the king’s lucky star.” The Water-Bearer is not a very conspicuous constellation, as it does not contain any brilliant stars; it has been represented from time immemorial as a man pouring water out of a vase, but the Arabs—who being Moslems, and hence forbidden to picture the human figure—have represented this constellation as a saddled mule, carrying on its back two water skins.

In the Eastern part of the sky we now see that the summer constellations are again beginning to appear. Pegasus is nearly North; while the “Chained Lady,” Andromeda, will be seen rising below it in the North-East To the right of Andromeda, Triangulum, the (Northern) Triangle, and the first constellation of the Zodiac, Aries, tin Ram, are now above the horizon. Above the Ram is Pisces, the Fishes, to the right of which is the extensive constellation of the “Sea Monster,” Cetus, now perfectly clear of the horizon; its brightest star ((3),    , will be seen

midway between the zenith and the Eastern horizon. “ Orion’s River,” Eridanus, is nearly all apparent; it will be observed twisting upwards from the Eastern horizon till it reaches the brilliant star, Ache mar, which is now between the zenith and the South-Eastern horizon. Phoenix is to the left of Achernar; while just above the South-Eastern horizon, Columba, “ Noah’s Dove,” will be noticed.

The Ship, Argo, stretches along the horizon to the South; its leading star, the brilliant Canopus, will be seen sparkling with great lustre near the horizon, between the South-East and the South. Above the star Canopus is Dorado, the Sword-Fish, and Reticulum, the Net, and above Reticulum is the Water Snake, between the Magellanic clouds—viz., Nebecula Major and Nebecula Minor; while between Hydras and Grus—which is directly overhead—is the small constellation of Toucan.

The constellation of Cetus having now appeared above the horizon, and remaining visible for several months, the ‘maximum’ of its variable star Omicron (Mira) will be observable, should the date fall within that period.

Pegasus is now favourably situated for observation. According to the old Greek legend, Pegasus, the Winged Horse, sprang forth from the head of Medusa when she was slain by Perseus (see p. 22). He flew up to heaven and dwelt with the immortals, being employed by Jupiter to carry thunder and lightning.

Another Greek legend relates that, by the favour of Athene (Minerva), the hero Bellerophon obtained the use of Pegasus to enable him to destroy the fire-breathing monster Chimaera. High in the air, Bellerophon shot his arrows at the monster in safety and destroyed it, thus preserving his own life from the wiles of a king who hoped that Bellerophon would perish in the adventure. Afterwards Bellerophon is said to have attempted to fly up to heaven on Pegasus, but Zeus (Jupiter), angry at his impious attempt, sent a gadfly to sting Pegasus, so that he would rear and unseat his rider. Bellerophon was flung off in mid air, and falling to the earth, was blinded.

A little west of (3 Andromedce, nearer the horizon, there is a faint misty patch, barely,'if at all, distinguishable in our latitudes. This is the Great Andromeda Nebula, which has been called the ‘ Queen of Nebulae.’

A faint ‘new star’ appeared in this nebula in 1885, and from brightness considerations it was thought that its distance might be of the order of 500,000 light-years. Recently, however, some ‘Cepheid ’ stars have been xound in the nebula, and if their evidence is to be trusted, the nebula must be situated at an appalling distance, as its light may take nearly a million years to reach the Earth. And it is decreasing its distance from us many

millions of miles every day ! Photographs reveal that it is spiral in form, and known to be a separate universe.

¿■31

The accents are pronounced as follows:—

â

as in

fate

ë

as in we

ï as in ice

ô as in

üas in unite

a

fat

e

,, met

i „ ül

0 „

odd

ú „

up

••

a

>>

arm

ë

,, water

• • • • • •

A

o „

orb

A

U »

urn

à

j)

sofa

• • • • •

• • « • • •

ÖÖ

food

• • t

• • •


Note :—This list follows the so-called English method of pronunciation, which is generally used for Latin and Gfeek proper names in English context.

Constellations.—For the genitives (g.) of names ending in -us -um, change the -us or -um into -i (pronounced i), as Lupus? (g.) Lupi. Those ending in a : change the a into ce (pronounced ë), as Mensa, Mensæ. Modern Constellations are marked * ; the original form of some of these, shortened from more cumbrous forms, are given in the footnote.

Andromeda, an-dr6m/e-daAndromeciap-22. Antlia, antTi-a ...    The Air Pump1

Apus, a/pus {g. a-pod'is) Bird of Paradise Aquarius, a-kwa'ri-us    The    Water-hearer

Aquila, ak'wi-la    ...    The Eagle

Ara, a'ra    ...    ... The Altar

Argo, ar'go (g., ar'g55s) Ship Argo (p.24) Aries, a'ri-ez' {g., a-rfe-tis) The Ram Auriga, o-ri'ga ...    The Charioteer

Bootes, bo-6'tez (g., -tis) The Herdsman Caelum, seTum ...    ...    The Chisel2

Camelopard us, ka-meTo-pard- us Giraffe Cancer, kan'ser {g., kan-kri) The Crab Canes Venatici, ka'nez ve-nat'-i-si, or -kl {g. kaTium ve-natT-ko'rum) Greyhounds Canis Major, ka'nis ma'-jer, {g. ma-jo'ris) „ Minor, ka'nis mi'ner {g. mi-no'ris)

The Greater and Lesser Dog Capricornus, kap-ri-kor'nus The Sea-goat Carina,* ka-ri'na    The Keel {Argo)

Cassiopeia, kas-i-6-pe'ya Cassiopeia (p.22) Centaurus, sen-to'rus    ...    The Centaur

Cepheus, se'fus or se'fe-us Cepheus (p.22) Cetus, se'tus The Sea Monster or Whale Chamaeleon,* ka-me'le-un {g.9 -le-on'tis)

The Chamceleon Circinus, sur'si-nus    The Compasses

Columba, ko-lum'ba    ... The Dove'6

Coma Berenices, ko'ma ber-e-ni'sez

Berenice’s Hair (p.5) Corona Australis, ko-ro'na os-tra'lis ,, Borealis, ,, bo-re-a'lis The Southern and Northern Crown


Corvus, kor'vus ...    ...    The Crow

Crater, kra'ter {g.9 krat'er-is) The Cup Crux, kruks, {g. krdosis)    ...    The Cross

Cygnus, sig'nus ...    ...    The    Swan

Delphinus, del-fl'nus    ...    The Dolphin

Dorado, d5-ra'do {g.,    -do5s)    Swordfish

Draco, dra'ko {g., drako'nis) Ihe Dragon Equuleus, e-kwoo'le-us The Little Horse Eridanus, e-rid'a-nus The River Eridanus Fornax, for'naks {g. for-nas'is) FurnaceGemini, jem'i-ni (</., -no'rum) Twms{p.25Grus, grus* {g.9 groo'is)    ...    The Crane

Hercules, her'ku-lez {g. lis) Hercules (p.26) Horologium,* hor-o-lo'ji-um    The Clock

Hydra, hi'dra ...    The    Water Snake

Hydrus, hi'drus ...    „    ,,

Indus, In'dus ...    ...    The Indiam

Lacerta, la-ser'ta    ...    The Lizard

Leo, le'o {g.9 le-6'nls) The Lion [Lion Minor, mi'ner {g. mi-nor'is) Lesser Leptis, le'pus {g., lep'or-is)    The Hare

Libra, li'bra    ...    ...    The Balances

Lupus, lu'pus    ...    ...    The Wolf

Lynx,* links {g,9 -lins'is) ...    The Lynx

Lyra, ll'ra    ...    ...    The Lyre

[MALUS,*maTus,(now Pyxis) Mast of Argo] Mensa,* men'sa ... Table MountainMicroscopium,* mi-kro-sko'p-i-iim

The Microscope    [The Unicorn

Monoceros,* mo-nos'er-Ss {g.9 er-6'tis) Musca,* mus'ka ...    The [Southern] Fly 6

Norm a,* nor'ma ...    ... The Square

Octans,* ok'tanz (gr., ok-tan'tis) Octant7


Ophiuchus, of-i-u'kus The Serpent-bearer Orion, o-ri'on {g. or-i-5'nis) The Hunter Pavo,* pa'vo {g., pa-vo'nis) The Peacock Pegasus, peg'a-sus    Pegasus {p.S'])

Perseus, pur'sus or piir'se-us Perseus{p.22) PHoeNix,* fe'niks {g., fe-nl'cis) The Phoenix Pictor,* pik'tSr {g.. -tor'is) The Painter^ Pisces, pis'ez {g.9 pis'i-um) The Fishes Piscis Australis, pis'is os-traTis

'llie Southern Fish Puppis,* pup'is {g.9 pup'is) Poop {of Argo) Pyxis,* pik'sis (g.9 pik'sis) The Compass 9’ Reticulum,* re-tik'u-lum ... The Net10, Sagitta. sa-jit'a ...    ... The Arrow

Sagittarius, saj-i-ta'ri-us... The Archer Scorpio, skor'pi-5 {g.9 -o'nis) The Scorpion Scorpius, skor'pi-us {g.9 skor'pi-I) „ Sculptor,* skulp'ter (g., -to'ris) Sculptor11 Scutum,* sku'tum    ... The Shield12'

Serpens, ser'penz {g., ser-pen'tis) Serpent Sextans,* seks'tanz {g. -tan'tis) Sextant1S-Taurus to'rus ...    ... The Bull

Telescopium,* tele-sko'pi-um The Telescope TouCANUS,*to5-ka'nus The American Goose Triangulum, tri-an'gu-lum The Triangle ,, Australe,* „ -ostraTe Southern „ Ursa Major, ur'sa ma'jer (t^.urse ma-jo'ris) The Greater Bear [The Lesser Bear ,, Minor, ur'sa mfner {g.9 ur'se mi-nd'ris) Vela,* ve'la {g.. ve-lo'rum) Sails {of Argo) Virgo, vur'go {g.9 vur'ji-nis) The Virgin Volans,* vo'lanz (g.9 -lan'tis) Flying Fish 14 Vulpecula,* vul-pek'u-la ... The Fox15>


Original Forms. a Antlia Pneumatica. 2Caela Sculptoris, The Sculptor's Chisels.    3 Columba Noachii, Noah's Dove.    4 Fornax Chemica,

The Chemical Furnace. 5 Mons Mensse. 6 Apis Musca Australis. 7 Octans Hadleianus, Hadley's Octant.    8 Equuleus Pictoris, The Painter's Easel.

9 Pyxis Nautica, The Mariner's Compass. 10 Reticulum Rhomboidalis, The Rhomboidal Net. u Apparatus Sculptoris, The Sculptor s Workshop. 12 Scutum Sobieskii, Sobieskii's Shield.    13 Sextans Uranise, Urania's Sextant. 14 Piscis Volans. 15 Vulpecula et Anser, The Fox and the Goose.

Star and (p. 18) Cluster Names, Many of these, transliterated or corrupted from the Arabic, have no standard spellings— Arneb, Arnab; Caph, Chaph; Cebalrai, Kelbalrai; Tarazed, Trazed, &c. The spellings below follow those in Norton’s Star Atlas.

Baten Kaitos, bä't’n-ki'tös Bellatrix, be-lä'triks Benetnasch, bé-nét'násh Betelgeuse, bet-el-güz'

Canopus, ka-nö'püs Capella, ka-péTa Caph9 käf

Castor, kás'tér, käs'ter Cor Caroli, kor kar'5-lí „ Hydrce9 kòr hi'dre    .

,, Leonis, le-ö'ms ,, Scorpionis, kór skór-pí-o'nís ,, Scorpii, skor'pi-i „ Serpentis, kòr sér-pén'tís Cursa, kür-sä'

Denebola, de-neb'-ö-lä

Deneb Algiedi, dén'éb äl-je'di

Diphda, dif'dä

Dubhe, dööb'he

Electra, è-lék'tra

Enif, Eniph,enTf

Errai, är-räi'

Etamin, ét-á-mín'

Fomalhaut, fö'mäl-hot, -mäl-5 Gomeisa, gö-rm'sä Hamal, häm'dl Homam, hö-mäm'

Hyades, hl'ä-dez Izar, e-zär'

Kaitain, kí-táín'


Achernar, á'kér-nar Albireo, al-bi're-o Alchiba, äl-ki-bä'

Alcor, äl-kör'

Alcyone, äl-sTö-ne Aldebaran, al-déb'á-ran Alderamin, äl-de-rä'nnn Algeiba, al-jé'bá Algenib. al-gén'íb Algol, äl'göl, äl-göT Algorab, äl-gö-räb' Alhena, al-hén'á Alioth, alí-otlT Alkalurops, äl-kä-lü'röps Alkes, al-kéz'

Aimak, äl-mäk'

Alnilam, äl-m-läm' Alphard, äl-färd' Alphecca, al-fek'á Alpheratz. al-fe'räts Alphirk, äl-fürk' Aishain, äl-shä'm Altair, äl-tä'ir A Iwaid, äl -wä'id Antares, än-tä'rez Arcturus, ärk-tü'rüs Arided, ár-í-ded'

Arneb, är'neb Asterope, äs-ter'ö-pe Atlas, ät'läs

ns p. 32


Kaus Australis, kós ós-traTÌs Kelb al Rai, kelb-äl-räi' Kocab, kö'kab Kornephoros, kor-lief'ö-rüs Maia, mä'ya, mi-ä'

Markab mär'käb Mebsuta, meb-söö'ta Megrez, meg'rez Menkalinan, men-käl-i-nän' Menkar, -kob, men'kär Merak, me'räk Merope, mer'ö-pe Mesarthim, mes-är-tim' Mintaka, min'ta-kä Mira, mi'ra Mirac, mi'räk, me'räk Mirfak, mir'fäk Mirzam, mir'zäm Mizar, mTzär Nath, nàtlT Nekkar, nék-kar'

Phakt, fäkt Phecda, fek'dä Pleiades, pii' or ple'ä-dez Pleione, pli-ö'ne Polaris, pö-lä'ns Pollux, pöl'üks Prcesepe, pré-sé'pè Procyon, prö'si-on Ras Algeti, ras äl-je-te'

Rastaban, ras-ta-bán'

Ras Alhague, rás äl-hä'gwe Regulus, reg'ü-lús Rigel, rl'gël, rï'jël Sadalmelik, sád-al-meTik Sadalsud, sad-äl-sööd'

Scheat9 she-ät'

Schedar, shëd'àr Sheliak, shèhiak Sheratan, shër'â-tan'

Sirius, sir'i-ús Skat, skät Spica, sphká Sulaphat, söö-la-fät'

Talitha, tâ-lë'tà Tarazed, tär a-zëd Taygeta, tâ-ïjrë-tâ Thuban, thöö-ban'

Unukalhay, ü-núk'al-ha;

Vega, vë'ga

Vindemiatrix, vïn-dë-mï-ârtrik&

Wasat, wá'sát

Zaurak, zo'räk

Zawijah, zâ'vë-jâ

Zozca, Zosma, zos'kà, zos'mà

Zuben el Genubi, zôô-bën' ël jë-

nôô'bëf

,, el Hakrabi, ël ha-krà'bë

,, el diamoli, ël shà-mâTë i Zubenesch, zoo-bën'ësh