As to appearance, the Earth may be consider’d as being the center of the Heavens.
Hence it follows, that tho’ we approach nearer to some fixed Stars at one time of the year than we do at the opposite, and that by the whole length of the diameter of the Earth’s orbit; yet this distance being so small in comparison with the distance of the fixed Stars, their magnitudes or positions cannot thereby be sensibly altered; therefore we may always, without error, suppose ourselves to be in the same centerof the Heavens, since we always have the same visible prospect of the Stars without any alteration.
The fixed Stars are Suns.
If a spectator was placed as near to any fixed Star, as we are to the Sun, he would there observe a body as big, and every way like, as the Sun appears to us: and our Sun would appear to him no bigger than a fixed Star: and undoubtedly he would reckon the Sun as one of them in numbering the Stars. Wherefore since the Sun differeth nothing from a fixed Star, the fixed Stars may be reckoned so many Suns.
The fixed Stars are at vast distance from each other.
It is not reasonable to suppose that all the fixed Stars are placed at the same distance from us; but it is more probable that they are every where interspersed thro’ the vast indefinite space of the universe; and that there may be as great a distance betwixt any two of them, as there is betwixt our Sun and the nearest fixed Star. Hence it follows, why they appear to us of different magnitudes, not because they really are so, but because they are at different distances from us; those that are nearest excelling in brightness and lustre those that are most remote, who give a fainter light, and appear smaller to the eye.
The distribution of the Stars into 6 classes.
OfTelescopical Stars.
The astronomers distribute the Stars into several orders or classes; those that are nearest to us, and appear brightest to the eye, are called Stars of the first magnitude; those that are nearest to them in brightness and lustre, are called Stars of the second magnitude; those of the third class, are stiled Stars of the third magnitude; and so on, until we come to the Stars of the sixth magnitude, which are the smallest that can be discerned by the naked eye. There are infinite numbers of smaller Stars, that can be seen through telescopes; but these are not reduced to any of the six orders, and are only calledTelescopical Stars. It may be here observed, that tho’ the astronomers have reduced all the Stars that are visible to the naked eye, into some one or other of these classes, yet we are not to conclude from thence that all the Stars answer exactly to some or other of these orders; but there may be in reality as many orders of the Stars, as they are in number, few of them appearing exactly of the same bigness and lustre.
The Stars digested into constellations
The ancient astronomers, that they might distinguish the Stars, in regard to their situation and position to each other, divided the whole starry firmament into SeveralAsterisms, or systems of Stars, consisting of those that are near to one another. TheseAsterismsare calledConstellations, and are digested into the forms of some animals; as Men, Lyons, Bears, Serpents,&c.or to the images of some known things; as, of a Crown, a Harp, a Triangle,&c.
Zodiac.
The starry firmament was divided by the ancients into 48 images, or constellations; twelve of which they placed in that part of the Heavens wherein are the planes of the Planetary orbits; which part is called theZodiac, because most of the constellations placed therein resemble some living creature. The two regions of the Heavens that are on each side of theZodiac, are called the North and South parts of the Heavens.
Constellations within the Zodiac.
The constellations within theZodiacare, 1.Aries, theRam; 2.Taurus, theBull; 3.Gemini, theTwins; 4.Cancer, theCrab; 5.Leo, theLion; 6.Virgo, theVirgin; 7.Libra, theBalance; 8.Scorpio, theScorpion; 9.Sagittarius, theArcher; 10.Capricornus, theGoat; 11.Aquarius, theWater-Bearer; and, 12.Pisces, theFishes.
Northern constellations.
The constellations on the North side of theZodiacare Twenty-one,viz.theLittle Bear; theGreat Bear; theDragon;Cepheus, a king ofEthiopia;Bootes, the keeper of theBear; theNorthern Crown;Herculeswith his Club, watching theDragon; theHarp; theSwan;Cassiopeia;Persius;Andromeda; theTriangle;Auriga;Pegasus, or theFlying Horse;Equuleus; theDolphin; theArrow; theEagle;Serpentarius; and theSerpent.
Southern constellations.
The constellations noted by the ancients on the South side of theZodiac, were fifteen,viz.theWhale; the riverEridanus; theHare;Orion; theGreat Dog;Little Dog; the ShipArgo;Hydra; theCentaur; theCup; theCrow; theWolf; theAltar; theSouthern Crown; and theSouthern Fish. To these have been lately added the following,viz.ThePhœnix; theCrane; thePeacock; theIndian; theBird of Paradise; theSouthern Triangle; theFly;Cameleon; theFlying Fish;Toucan, or theAmerican Goose; theWater Serpent, and theSword Fish. The ancients placed those particular constellations or figures in the Heavens, either to commemorate the deeds of some great man, or some notable exploit or action; or else took them from the fables of their religion,&c. And the modern astronomers do still retain them, to avoid the confusion that would arise by making new ones, when they compare the modern observations with the old ones.
Unformed Stars.
Some of the principal Stars have particular names given them, asSyrius,Arcturus,&c.There are also several Stars that are not reduced into constellations, and these are calledUnformed Stars.
TheGalaxy, orMilky Way.
Besides the Stars visible to the naked eye, there is a very remarkable space in the Heavens, called theGalaxy, orMilky Way. This is a broad circle of a whitish hue, like milk, going quite round the whole Heavens, and consisting of an infinite number of small Stars, visible thro’ a telescope, tho’ not discernable by the naked eye, by reason of their exceeding faintness; yet with their light they combine toillustrate that part of the Heavens where they are, and to cause that shining whiteness.
The places of the fixed Stars, or their relative situations one from another, have been carefully observed by astronomers, and digested into catalogues. The first among theGreeks, who reduced the Stars into a catalogue, wasHypparchus, who, from his own observations, and of those who lived before him, inserted 1022 Stars into his catalogue, about 120 years before the ChristianÆra: This catalogue has been since enlarged and improved by several learned men, to the number of 3000, of which there are a great many telescopical, and not to be discerned by the naked eye; and these are all ranked in the catalogue as the Stars of the seventh magnitude.
It may seem strange to some, that there are no more than this number of Stars visible to the naked eye; for sometimes in a clear night they seem to be innumerable: but this is only a deception of our sight, arising from their vehement sparkling, while we look upon them confusedly, without reducing them into any order; for there can seldombe seen above 1000 Stars in the whole Heavens with the naked eye at the same time; and if we should distinctly view them, we shall not find many but what are inserted upon a goodCelestialGlobe.
Altho’ the number of Stars that can be discerned by the naked eye are so few, yet it is probable there are many more which are beyond the reach of our optics, for through telescopes they appear in vast multitudes, every where dispersed throughout the whole Heaven; and the better our glasses are, the more of them we still discover. The ingenious Dr.Hookhas observed 78 Stars in thePleiades, of which the naked eye is never able to discern above 7; and inOrion, which has but 80 Stars in theBritishcatalogue (and some of them telescopical) there has been numbered 2000 Stars.
An idea of the Universe.
Those who think that all these glorious bodies were created for no other purpose than to give us a little dim light, must entertain a very slender idea of the Divine Wisdom; for we receive more light from theMoonitself, than from all theStarsput together. And since thePlanetsare subject to the same laws of motion with ourEarth, andsome of them not only equal, but vastly exceed it in magnitude, it is not unreasonable to suppose, that they are all habitable Worlds. And since theFixed Starsare no ways behind ourSun, either in bigness or lustre, is it not probable, that each of them have a system ofPlanetary Worldsturning round them, as we do round our Sun? And if we ascend as far as the smallest Star we can see, shall we not then discover innumerable more of these glorious bodies, which now are altogether invisible to us? And soad infinitum, thro’ the boundless space of the universe. What a magnificient idea must this raise in us of theDivine Being! Who is every where, and at all times present, displaying his Divine Power, Wisdom and Goodness, amongst all his Creatures!