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7. A GLOBULAR CLUSTER between the mouths of Pegasus and Eqüleus, about 4° northwest of &; R. A. 21h. 22m. 13s.; Dec. N. 11° 27' 4". Map IX., Fig. 65. It is laid down as a nebula on Map II., but with a good instrument it is resolved into stars, with straggling outliers, as shown in the diagram.
8. An ELONGATED NEBULA in the animal's mane, about 8° due south of Markab; R. A. 22h. 56m. 58s.; Dec. N. 11° 27' 9". A very faint and difficult object.
EQULEUS, VEL EQUI SECTIO (THE LITTLE HORSE, OR THE HORSE'S HEAD).—MAP II.
234. This Asterism, or small cluster of stars, is situated about 7° W. of Enif, in the head of Pegasus, and about half-way between it and the Dolphin. It is on the meridian at 8 o'clock, on the 11th of October. It contains ten stars, of which the four principal are only of the 4th magnitude. These may be readily distinguished by means of the long irregular square which they form. The two in the nose are much nearer together than the two in the eyes: the former being 1° apart, and the latter 21. Those in the nose are uppermost, being 4° N. of those in the eyes. This figure also is in an inverted position. These four stars are situated 10° or 12° S. E. of the diamond in the Dolphin's head. Both of these clusters are noticeable on account of their figure rather than their brilliancy.
This constellation is supposed to be the brother of Pegasus, named Celeris, given by Mercury to Castor, who was so celebrated for his skill in the management of horses; others take him to be the celebrated horse which Neptune struck out of the earth with his trident, when he disputed with Minerva for superiority. The head only of Celeris is visible, and this, also, is represented in an inverted position.
Four of the principal stars in this little group are double-namely, ß, d, & and 2. B is rather a star with a companion; R. A. 21h. 14m. 57s.; Dec. N. 6° 07′ 9′′. The other three will easily be found from their proximity to B.
AQUARIUS (THE WATER-BEARER).—MAP II.
235. This constellation is represented by the figure of a man pouring out water from an urn. It is situated in the Zodiac, immediately S. of the equinoctial, and bounded by the Little
234. Situation of Eqüleus? When on the meridian? Number of stars, and how distinguished? What further description?
HISTORY.-What suppositions respecting the origin of Eqüleus?
235. How is Aquarius represented? Its boundaries?
Horse, Pegasus, and the Western Fish on the N., the Whale on the E., the Southern Fish on the S. and the Goat on the W.
236. Aquarius is now the 12th in order, or last of the Zodiacal constellations; and is the name of the 11th sign in the ecliptic. Its mean declination is 14° S., and its mean right ascension 335°, or 22 hours, 20 min.; it being 1 hour and 40 min. W. of the equinoctial colure; its center is, therefore, on the meridian the 15th of October.
It contains one hundred and eight stars; of which the four largest are all of the 3d magnitude.
"His head, his shoulders, and his lucid breast,
237. The northeastern limit of Aquarius may be readily distinguished by means of four stars of the 4th magnitude, in the hand and handle of the urn, so placed as to form the letter Y, very plainly to be seen, 15° S. E. of Enif, or 18° S. S. W. of Markab, in Pegasus; making with the two latter nearly a right angle.
About 4% W. of the figure is El Melik, a star of the 3d magnitude, in the E. shoulder, and the principal one in this constellation. 10° S. W. of El Melik, is another star of the same magnitude, situated in the W. shoulder, called Sad es Saud.
Ancha, of the 4th magnitude, is in the right side, 8° S. of El Melik. 9° E. of Ancha, is another star of the 4th magnitude, whose letter name is Lambda.
Scheat, of the 3d magnitude, lying below the knee, is situated 8% S. of Lambda; and 14° S. of Scheat, the brilliant star Fomalhaut, of between the 1st and 2d magnitudes, terminates the cascade in the mouth of the Southern Fish. This star is common to both these constellations, and is one of those from which the lunar distance is computed for ascertaining the longitude at sea. It culminates at 9 o'clock on the 22d of October.
Fomalhaut, Deneb Kaitos, and Alpha in the head of the Phoenix, make a large triangle, whose vertex is in Deneb Kaitos. Those two stars of the fourth magnitude, situated 4° S. of Sad es Saud, and nearly the same distance from Ancha, are in the tail of Capricorn. They are about 2° apart. The western one is called Deneb Algedi.
The rest of the stars in the cascade are quite small; they may be traced from the ietter Y, in the urn, in a southeasterly direction toward the tail of Cetus, from which the cascade suddenly bends off near Scheat, in an opposite course, and finally disappears in the mouth of the Southern Fish, 30° 8. of Y.
This constellation is the famous Ganymede, a beautiful youth of Phrygia, son of Tros, king of Troy, or, according to Lucian, son of Dardanus. He was taken up to heaven by Jupiter as he was tending his father's flocks on Mount Ida, and became the cup-bearer of the gods in place of Hebe. There are various opinions, however, among the ancients respecting its origin. Some suppose it represents Deucalion, who was placed among the stars after the celebrated deluge of Thessaly, 1500 years before the birth of our Saviour; while others think it designed to commemorate Cecrops, who came from Egypt to Greece, founded Athens, established science, and introduced the arts of polished life.
The ancient Egyptians supposed the setting or disappearance of Aquarius caused the Nile to rise, by the sinking of his urn in the water. In the Zodiac of the Hebrews, Aquarius represents the tribe of Reuben.
Its order in the signs and constellations? Number and size of its stars? distinguish the northeast limit? What said of El Melik? Of Sad es Saud? Of Ancha, Lambda, Scheat, &c.
HISTORY.-Story of Ganymede, and Jupiter? What other myth? Idea of the Egyp tains? Hebrew Zodiac?
1. a AQUARII (Phard)-A star with a minute companion on the Water-bearer's left shoulder; R. A. 21h. 57m. 38s.; Dec. S. 1° 05′ 07′′. A 3, pale yellow; B 18, grey; and another star in the field on a line with A and B. Markab is on a line joining Alpheratz and Phard, and about half way between them.
2. B AQUARII (Sad-al-melik)—A star with a companion on the right shoulder; R. A. 21h. 23m. 07s.; Dec. N. 6° 16' 04". A 3, pale yellow; B 15, blue. A very delicate object. 3. y AQUARII-A delicate but wide DOUBLE STAR, on the water-pot; R. A. 22h. 18m. 23s.; Dec. S. 2° 11′ 05′′. A 4, greenish tinge; B 14, purple. It is about 4° east-by-south from Sad-al-melik.
4. S AQUARII—A BINARY STAR in the left wrist, about 6° east from Sadalmelik; R. A. 22h. 20m. 35s.; Dec. S. 0° 50′ 02′′. A 4, very white; B 4%, white.
5. T' AQUARII—A fine DOUBLE STAR in the left leg, one third of the way from Fomalhaut to Pegasi; R. A. 22h. 89m. 13s.; Dec. S. 14° 53′ 09'. A 6, white; B 9%, pale garnet. 6. AQUARII—A DOUBLE STAR in the stream, being the first of three similar stars marked 1, 2, 3; R. A. 23h. 07m. 30s.; Dec. S. 9° 57′ 05′′. A 51⁄2, orange tint; B 9, sky blue. It is about one-third of the way from Fomalhaut to a Andromeda. Several other beautiful double stars east of Scheat, in the stream, as shown on the map.
7. A FINE GLOBULAR CLUSTER near the neck of Aquarius, about 5° north-half-east from B; R. A. 21h. 23m. 07s.; Dec. S. 6° 16' 04". A cluster of exceedingly small stars, which has been likened to "a heap of fine sand." Several telescopic outliers in the field. Map VIII., Fig. 66.
8. A PLANETARY NEBULA in the middle of the scarf; R. A. 20h. 55m. 27s.; Dec. S. 11° 59' 03". About 12° east of a Capricorni, where a line from the Eagle's tail over Antinoi, and as far again, reaches it. It is bright to its very disc, and but for its pale blue tint, would be a very miniature of Venus.
PISCES AUSTRALIS (THE SOUTHERN FISH).—MAP II.
238. This constellation is directly S. of Aquarius, and is represented as a fish drinking the water which Aquarius pours from his urn. Its mean declination is 31° S. and its mean right ascension and time of passing the meridian are the same as those of Aquarius, and it is seen on the meridian at the same time, viz. on the 15th of October. It contains 24 visible stars, of which one is of the 1st magnitude, or between the 1st and 2d, two are of the 3d, and five of the 4th. The first and most beautiful of all is Fomalhaut, situated in the mouth. This is 14° directly S. of Scheat in Aquarius, and may be seen passing the meridian low down in the southern hemisphere, on the 22d and 23d of October. Its position in the heavens has been determined with the greatest possible accuracy, to enable navigators to find their longitude at sea.
The mode of doing this cannot be explained here. The proolern is one of some difficulty. It consists in finding the angular distance between some star whose position is well known,
TELESCOPIC OBJECTS.-Alpha? Beta? Gamina? Zeta? Tau? Psi? What clusters, and where shown on the map? What nebula?
238. Situation of Pisces Australis? How represented? When on the meridian? Number of stars? Magnitude? The principal star? How situated? What use made of it? What said of the method of finding the longitude by the moon and stars?
and the moon when she is passing near it; also, the altitude of each, at the same instant, with good sextants. These data furnish the elements of a spherical triangle, the solution of which, after various intricate corrections, is made to result in the longitude of the given place.-See note to Arietes. In 1714, the British Parliament offered a reward of 10,000 pounds sterling, to any man who should discover a method of determining the longitude within 1°, or 60 geographical miles of the truth; 15,000 pounds to the man who should find it within 40 miles, and 20,000 pounds, if found within 30 miles. These rewards in part, have been since distributed among eminent mathematicians, in Europe, agreeably to the respective merits of their discoveries.
This constellation is supposed to have taken its name from the transformation of Venus into the shape of a fish, when she fled, terrified at the horrible advances of the monster Typhon, as we have related in the mythology of the Fishes.-(See Pisces.)
a PISCES AUSTRALIS-A first magnitude star with a very distant companion, in the eye of the fish; R. A. 22h. 48m. 48s.; Dec. S. 30° 28′ 03′′. A 1, reddish; B9%1⁄2, dusky blue.
LACERTA (THE LIZARD).—MAP II.
239. This is a small and obscure modern constellation, between the tail of Cygnus and the head of Andromeda. It has one star of the 4th magnitude, eight of the 5th, and a few much smaller.
240. Between Lacerta and Andromeda a singular looking figure appears on the map, called Gloria Frederica; or Frederic's Glory. It was inserted among the constellations by Bode, in 1787, as a compliment to Frederic II., of Prussia. It consists of a crown, a laurel, a sword, and a pen, to represent the monarch, the hero, the sage, and the pacificator. But the constellation was not recognized by astronomers, and, as such, has already passed from the heavens.
1. A neat DOUBLE STAR on the tip of the Lizard's tail; R. A. 22h. 11m. 56s.; Dec. N. 86° 58′ 01′′. A 6%, pale white; B 9, livid.
2. A delicate but wide DOUBLE STAR on the shoulder; R. A. 22h. 14m. 25s.; Dec. N. 45° 48′ 09". A 5, pale yellow; B 13, orange tint. A line from Polaris carried by the east of Cepheus tiara, and 11° further, will find it the lucida of a fine galaxy field.
8. A WIDE DOUBLE STAR near the end of the tail, the southern star of three forming a neat triangle; R. A. 22h. 82m. 05s.; Dec. N. 88° 13′ 2′′. A 6, white; B 10, violet.
4. A DELICATE TRIPLE STAR in the space between the Lizard's back and the left hand of Andromeda; R. A. 22h. 49m. 06s.; Dec. N. 40° 45' 1". A 6, bright white; B. 15, pale blue; C 9, reddish; a fourth star at a distance. A very difficult object; claimed by some for Andromeda, but usually classed as belonging to the Lizard.
HISTORY.-Supposed origin of this constellation? TELESCOPIC OBJECTS.-Alpha? Where situated? 239. Describe Lacerta. Where situated?
240. What other small constellation near?
By whom inserted, when and why? Of what does it consist? To represent what? Is it recognized by astronomers?
TELESCOPIC OBJECTS.-What double stars in Lacerta? What tripie star? Quadruple? Cluster? Any of them shown on the map?
5. A QUADRUPLE STAR, the western one of the three forming the triangle at the end of the tail; R. A. 22h. 29m. 46s.; Dec. N. 38° 48′ 5'. About 20° northwest of Alpheratz. A and B 6, both white; C 11, greenish; D 10, blue.
6. A LARGE LOOSE CLUSTER in the Lizard's mouth; R. A. 22h. 08m. 59s.; Dec. N. 49° 05 1'. Stars from the 9th to the 14th magnitudes. A line carried from Polaris through the tiara of Cepheus, and 8° beyond, strikes it.
VARIABLE AND DOUBLE STARS-CLUSTERS AND NEBULE.
241. THE periodical variations of brilliancy to which some of the fixed stars are subject, may be reckoned among the most remarkable of their phenomena. Several stars, formerly distinguished by their splendor, have entirely disappeared; others are now conspicuous which do not seem to have been visible to the ancient observers; and there are some which alternately appear and disappear, or, at least, of which the light undergoes great periodic changes. Some seem to become gradually more obscure, as Delta in the Great Bear; others, like Beta in the Whale, to be increasing in brilliancy.
242. Some stars have all at once blazed forth with great splendor, and, after a gradual diminution of their light, again become extinct. The most remarkable instance of this kind is that of the star which appeared in 1572, in the time of Tycho Brahe. It suddenly shone forth in the constellation Cassiopeia, with a splendor exceeding that of stars of the first magnitude, even of Jupiter and of Venus, at their least distances from the earth; and could be seen with the naked eye, on the meridian, in full day! Its brilliancy gradually diminished from the time of its first appearance, and at the end of sixteen months it entirely disappeared, and has never been seen since. (See a more particular account of this phenomenon, page 35.)
Another instance of the same kind was observed in 1604, when a star of the first magnitude suddenly appeared in the right foot of Ophiuchus. It presented, like the former, all the phenomena of a prodigious flame, being, at first, of a dazzling white, then of a reddish yellow, and, lastly, of a leaden paleness; in which its light expired. These instances prove that the stars are subject to great physical revolutions. (Page 00)
243. A great number of stars have been observed whose light seems to undergo a regular periodic increase and diminution.
241. What said of the periodical variations of the stars? 242. What other remarkable phenomenon? What instances cited? What do these instances prove? 248. What