_Of the fixed Stars._
[Sidenote: Why the fixed Stars appear bigger when viewed by the bare eye
than when seen through a telescope.]
391. The Stars are said to be fixed, because they have been generally
observed to keep at the same distance from each other: their apparent
diurnal revolutions being caused solely by the Earth’s turning on its
Axis. They appear of a sensible magnitude to the bare eye, because the
retina is affected not only by the rays of light which are emitted
directly from them, but by many thousands more, which falling upon our
eye-lids, and upon the aerial particles about us, are reflected into our
eyes so strongly as to excite vibrations not only in those points of the
retina where the real images of the Stars are formed, but also in other
points at some distance round about. This makes us imagine the Stars to
be much bigger than they would appear, if we saw them only by the few
rays which come directly from them, so as to enter our eyes without
being intermixed with others. Any one may be sensible of this, by
looking at a Star of the first Magnitude through a long narrow tube;
which, though it takes in as much of the sky as would hold a thousand
such Stars, yet scarce renders that one visible.
[Sidenote: A proof that they shine by their own light.]
The more a telescope magnifies, the less is the aperture through which
the Star is seen; and consequently the fewer rays it admits into the
eye. Now since the Stars appear less in a telescope which magnifies 200
times than they do to the bare eye, insomuch that they seem to be only
indivisible points, it proves at once both that the Stars are at immense
distances from us, and that they shine by their own proper light. If
they shone by borrowed light they would be as invisible without
telescopes as the Satellites of Jupiter are: for these Satellites appear
bigger when viewed with a good telescope than the largest fixed Stars
do.
[Sidenote: Their number much less than is generally imagined.]
392. The number of Stars discoverable, in either Hemisphere, by the
naked eye, is not above a thousand. This at first may appear incredible,
because they seem to be without number: But the deception arises from
our looking confusedly upon them, without reducing them into any order.
For look but stedfastly upon a pretty large portion of the sky, and
count the number of Stars in it, you will be surprised to find them so
few. Or, if one considers how seldom the Moon meets with any Stars in
her way, although there are as many about her Path as in other parts of
the Heavens (the _Milky way_ excepted) he will soon be convinced that
the Stars are much thinner sown than he was aware of. The _British_
catalogue, which, besides the Stars visible to the bare eye, includes a
great number which cannot be seen without the assistance of a telescope,
contains no more than 3000, in both Hemispheres.
[Sidenote: The absurdity of supposing the Stars were made only to
enlighten our nights.]
393. As we have incomparably more light from the Moon than from all the
Stars together, it were the greatest absurdity to imagine that the Stars
were made for no other purpose than to cast a faint light upon the
Earth: especially since many more require the assistance of a good
telescope to find them out, than are visible without that Instrument.
Our Sun is surrounded by a system of Planets and Comets; all which would
be invisible from the nearest fixed Star. And from what we already know
of the immense distance of the Stars, the nearest may be computed at
32,000,000,000,000 of miles from us which is more than a cannon bullet
would fly in 7,000,000 of years. Hence ’tis easy to prove, that the Sun
seen from such a distance, would appear no bigger than a Star of the
first magnitude. From all this it is highly probable that each Star is a
Sun to a system of worlds moving round it though unseen by us;
especially, as the doctrine of a plurality of worlds is rational, and
greatly manifests the Power, Wisdom, and Goodness of the great Creator.
[Sidenote: Their different Magnitudes.]
394. The Stars, on account of their apparently various magnitudes, have
been distributed into several classes or orders. Those which appear
largest are called _Stars of the first magnitude_; the next to them in
lustre, _Stars of the second magnitude_, and so on to the _sixth_, which
are the smallest that are visible to the bare eye. This distribution
having been made long before the invention of telescopes, the Stars
which cannot be seen without the assistance of these instruments are
distinguished by the name of _Telescopic Stars_.
[Sidenote: And division into Constellations.]
395. The antients divided the starry Sphere into particular
Constellations, or Systems of Stars, according as they lay near one
another, so as to occupy those spaces which the figures of different
sorts of animals or things would take up, if they were there delineated.
And those Stars which could not be brought into any particular
Constellation were called _unformed Stars_.
[Sidenote: The use of this division.]
396. This division of the Stars into different Constellations or
Asterisms, serves to distinguish them from one another, so that any
particular Star may be readily found in the Heavens by means of a
Celestial Globe; on which the Constellations are so delineated as to put
the most remarkable Stars into such parts of the figures as are most
easily distinguished. The number of the antient Constellations is 48,
and upon our present Globes about 70. On _Senex_’s Globes are inserted
_Bayer_’s Letters; the first in the Greek Alphabet being put to the
biggest Star in each Constellation, the second to the next, and so on:
by which means, every Star is as easily found as if a name were given to
it. Thus, if the Star γ in the Constellation of the _Ram_ be mentioned,
every Astronomer knows as well what Star is meant as if it were pointed
out to him in the Heavens.
[Sidenote: The _Zodiac_.]
397. There is also a division of the Heavens into three parts. 1. The
_Zodiac_, (ζωδιακὸς) from ζώδιον _Zodion_ an Animal, because most of the
Constellations in it, which are twelve in number, are the figures of
Animals: as _Aries_ the Ram, _Taurus_ the Bull, _Gemini_ the Twins,
_Cancer_ the Crab, _Leo_ the Lion, _Virgo_ the Virgin, _Libra_ the
Balance, _Scorpio_ the Scorpion, _Sagittarius_ the Archer, _Capricornus_
the Goat, _Aquarius_ the Water-bearer, and _Pisces_ the Fishes. The
Zodiac goes quite round the Heavens: it is about 16 degrees broad, so
that it takes in the Orbits of all the Planets, and likewise the Orbit
of the Moon. Along the middle of this Zone or Belt is the Ecliptic, or
Circle which the Earth describes annually as seen from the Sun; and
which the Sun appears to describe as seen from the Earth. 2. All that
Region of the Heavens, which is on the north side of the Zodiac,
containing 21 Constellations. And 3. that on the south side, containing
15.
[Sidenote: The manner of dividing it by the antients.]
398. The antients divided the _Zodiac_ into the above 12 Constellations
or Signs in the following manner. They took a vessel with a small hole
in the bottom, and having filled it with water, suffered the same to
distil drop by drop into another Vessel set beneath to receive it;
beginning at the moment when some Star rose, and continuing until it
rose the next following night. The water fallen down into the receiver
they divided into twelve equal parts; and having two other small vessels
in readiness, each of them fit to contain one part, they again poured
all the water into the upper vessel, and strictly observing the rising
of some Star in the _Zodiac_, they at the same time suffered the water
to drop into one of the small vessels; and as soon as it was full, they
shifted it and set an empty one in it’s place. By this means, when each
vessel was full, they observed what Star of the _Zodiac_ rose; and
though not possible in one night, yet in many, they observed the rising
of twelve Stars, by which they divided the _Zodiac_ into twelve parts.
399. The names of the Constellations, and the number of Stars observed
in each of them by different Astronomers, are as follows.
Key to table P = _Ptolemy._ T = _Tycho._ H = _Hevelius._ F =
_Flamsteed._
The antient Constellations.
P T H F
Ursa minor The Little Bear 8 7 12 24
Ursa major The Great Bear 35 29 73 87
Draco The Dragon 31 32 40 80
Cepheus Cepheus 13 4 51 35
Bootes, _Arctophilax_ 23 18 52 54
Corona Borealis The northern Crown 8 8 8 21
Hercules, _Engonasin_ Hercules kneeling 29 28 45 113
Lyra The Harp 10 11 17 21
Cygnus, _Gallina_ The Swan 19 18 47 81
Cassiopea The Lady in her Chair 13 26 37 55
Perseus Perseus 29 29 46 59
Auriga The Waggoner 14 9 40 66
Serpentarius, _Ophiuchus_ Serpentarius 29 15 40 74
Serpens The Serpent 18 13 22 64
Sagitta The Arrow 5 5 5 18
Aquila, _Vultur_ The Eagle } 12 23
} 15 71
Antinous Antinous } 3 19
Delphinus The Dolphin 10 10 14 18
Equulus, _Equi sectio_ The Horse’s Head 4 4 6 10
Pegasus, _Equus_ The Flying Horse 20 19 38 89
Andromeda Andromeda 23 23 47 66
Triangulum The Triangle 4 4 12 16
Aries The Ram 18 21 27 66
Taurus The Bull 44 43 51 141
Gemini The Twins 25 25 38 85
Cancer The Crab 23 15 29 83
Leo The Lion } 30 49 95
} 35
Coma Berenices Berenice’s Hair } 14 21 43
Virgo The Virgin 32 33 50 110
Libra, _Chelæ_ The Scales 17 10 20 51
Scorpius The Scorpion 24 10 20 44
Sagittarius The Archer 31 14 22 69
Capricornus The Goat 28 28 29 51
Aquarius The Water-bearer 45 41 47 108
Pisces The Fishes 38 36 39 113
Cetus The Whale 22 21 45 97
Orion Orion 38 42 62 78
Eridanus, _Fluvius_ Eridanus, _the River_ 34 10 27 84
Lepus The Hare 12 13 16 19
Canis major The Great Dog 29 13 21 31
Canis minor The Little Dog 2 2 13 14
Argo Navis The Ship 45 3 4 64
Hydra The Hydra 27 19 31 60
Crater The Cup 7 3 10 31
Corvus The Crow 7 4 9
Centaurus The Centaur 37 35
Lupus The Wolf 19 24
Ara The Altar 7 9
Corona Australis The southern Crown 13 12
Pisces Australis The southern Fish 18 24
The New Southern Constellations.
Columba Noachi Noah’s Dove 10
Robur Carolinum The Royal Oak 12
Grus The Crane 13
Phœnix The Phenix 13
Indus The Indian 12
Pavo The Peacock 14
Apus, _Avis Indica_ The Bird of Paradise 11
Apis, _Musca_ The Bee or Fly 4
Chamæleon The Chameleon 10
Triangulum Australis The South Triangle 5
Piscis volans, _Passer_ The Flying Fish 8
Dorado, _Xiphias_ The Sword Fish 6
Toucan The American Goose 9
Hydrus The Water Snake 10
_Hevelius_’s Constellations made out of the unformed Stars.
_Hevelius._ _Flamsteed._
Lynx The Lynx 19 44
Leo minor The Little Lion 53
Asterion & Chara The Greyhounds 23 25
Cerberus Cerberus 4
Vulpecula & Anser The Fox and Goose 27 35
Scutum Sobieski Sobieski’s Shield 7
Lacerta The Lizard 10 16
Camelopardalus The Camelopard 32 58
Monoceros The Unicorn 19 31
Sextans The Sextant 11 41
[Sidenote: The _Milky Way_.]
400. There is a remarkable track round the Heavens, called the _Milky
Way_ from its peculiar whiteness, which is owing to a great number of
Stars scattered therein; none of which can be distinctly seen without
telescopes. This track appears single in some parts, in others double.
[Sidenote: Lucid Spots.]
401. There are several little whitish spots in the Heavens, which appear
magnified, and more luminous when seen through telescopes; yet without
any Stars in them. One of these is in _Andromeda_’s girdle, first
observed _A. D._ 1612, by _Simon Marius_; and which has some whitish
rays near its middle: it is liable to several changes, and is sometimes
invisible. Another is near the Ecliptic, between the head and bow of
_Sagittarius_: it is small, but very luminous. A third is on the back of
the _Centaur_, which is too far South to be seen in _Britain_. A fourth,
of a smaller size, is before _Antinous_’s right foot; having a Star in
it, which makes it appear more bright. A fifth is in the Constellation
of _Hercules_, between the Stars ζ and η, which spot, though but small,
is visible to the bare eye if the sky be clear and the Moon absent.
[Sidenote: Cloudy Stars.