When you look at the firmament on a clear Autumnal or Winter evening, it appears so thickly studded with stars, that you would perhaps imagine that the task of learning even the brightest of them would be almost hopeless. Let me assure you, this is all a mistake. On the contrary, it is a very easy task to become acquainted with the names and positions of the stars of the first magnitude, and of the leading constellations. If you will give a few evenings to the study, you will be surprised to find, both how rapidly you can form these new acquaintances, and how deeply you will become interested in them. I would advise you, at first, to obtain, for an evening or two, the assistance of some friend who is familiar with the stars, just to point out a few of the most conspicuous constellations. This will put you on the track, and you will afterwards experience no difficulty in finding all the constellations and stars that are particularly worth knowing; especially if you have before you a map of the stars, or, what is much better, a celestial globe. It is a pleasant evening recreation for a small company of young astronomers to go out together, and learn one or two constellations every favorable evening, until the whole are mastered. If you have a celestial globe, rectify it for the evening; that is, place it in such a position, that the constellations shall be seen on it in the same position with respect to the horizon, that they have at that moment in the sky itself. To do this, I first elevate the north pole until the number of degrees on the brass meridian from the pole to the horizon corresponds to my latitude, (forty-one degrees and eighteen minutes.) I then find the sun's place in the ecliptic, by looking for the day of the month on the broad horizon, and against it noting the corresponding sign and degree. I now find the same sign and degree on the ecliptic itself, and bring that point to the brass meridian. As that will be the position of the sun at noon, I set the hour-index at twelve, and then turn the globe westward, until the index points to the given hour of the evening. If I now inspect the figures of the constellations, and then look upward at the firmament, I shall see that the latter are spread over the sky in the same manner as the pictures of them are painted on the globe. I will point out a few marks by which the leading constellations may be recognised; this will aid you in finding them, and you can afterwards learn the individual stars of a constellation, to any extent you please, by means of the globes or maps. Let us begin with the Constellations of the Zodiac, which, succeeding each other, as they do, in a known order, are most easily found.
Aries (the Ram) is a small constellation, known by two bright stars which form his head, Alpha and Beta Arietis. These two stars are about four degrees apart; and directly south of Beta, at the distance of one degree, is a smaller star, Gamma Arietis. It has been already intimated that the Vernal equinox probably was near the head of Aries, when the signs of the zodiac received their present names.
Taurus (the Bull) will be readily found by the seven stars, or Pleiades, which lie in his neck. The largest star in Taurus is Aldebaran, in the Bull's eye, a star of the first magnitude, of a reddish color, somewhat resembling the planet Mars. Aldebaran and four other stars, close together in the face of Taurus, compose the Hyades.
Gemini (the Twins) is known by two very bright stars, Castor and Pollux, five degrees asunder. Castor (the northern) is of the first, and Pollux of the second, magnitude.
Cancer (the Crab.) There are no large stars in this constellation, and it is regarded as less remarkable than any other in the zodiac. It contains, however, an interesting group of small stars, called Præsepe, or the nebula of Cancer, which resembles a comet, and is often mistaken for one, by persons unacquainted with the stars. With a telescope of very moderate powers this nebula is converted into a beautiful assemblage of exceedingly bright stars.
Leo (the Lion) is a very large constellation, and has many interesting members. Regulus (Alpha Leonis) is a star of the first magnitude, which lies directly in the ecliptic, and is much used in astronomical observations. North of Regulus, lies a semicircle of bright stars, forming a sickle, of which Regulus is the handle. Denebola, a star of the second magnitude, is in the Lion's tail, twenty-five degrees northeast of Regulus.
Virgo (the Virgin) extends a considerable way from west to east, but contains only a few bright stars. Spica, however, is a star of the first magnitude, and lies a little east of the place of the Autumnal equinox. Eighteen degrees eastward of Denebola, and twenty degrees north of Spica, is Vindemiatrix, in the arm of Virgo, a star of the third magnitude.
Libra (the Balance) is distinguished by three large stars, of which the two brightest constitute the beam of the balance, and the smallest forms the top or handle.
Scorpio (the Scorpion) is one of the finest of the constellations. His head is formed of five bright stars, arranged in the arc of a circle, which is crossed in the centre by the ecliptic nearly at right angles, near the brightest of the five, Beta Scorpionis. Nine degrees southeast of this is a remarkable star of the first magnitude, of a reddish color, called Cor Scorpionis, or Antares. South of this, a succession of bright stars sweep round towards the east, terminating in several small stars, forming the tail of the Scorpion.
Sagittarius (the Archer.) Northeast of the tail of the Scorpion are three stars in the arc of a circle, which constitute the bow of the Archer, the central star being the brightest, directly west of which is a bright star which forms the arrow.