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W. of Arcturus-three very brilliant stars of similar magnitude that form a large equilateral triangle, pointing to the S. Arcturus and Denebola are also the base of a similar triangle on the north, terminating in Cor Caroli, which, joined to the former, constitutes the Diamond of Virgo.
162. The length of this figure, from Cor Caroli, on the north, to Spica Virginis on the south, is 50°. Its breadth, or shorter diameter, extending from Arcturus on the east to Denebola on the west, is 351°. Spica may otherwise be known by its solitary splendor, there being no visible star near it except one of the 4th magnitude, situated about 1° below it, on the left.
The position of this star in the heavens, has been determined with great exactness for the benefit of navigators. It is one of the stars from which the moon's distance is taken for determining the longitude at sea. Its situation is highly favorable for this purpose, as it lies within the moon's path, and little more than 2° below the earth's orbit.
Its right ascension being 199°, it will come to our meridian at 9 o'clock about the 28th of May, in that point of the heavens where the sun is at noon about the 20th of October.
163. Beta, called also Zavijava, is a star of the 3d magnitude, in the shoulder of the wing, 74° W. of Eta, with which and Gamma it forms a line near the Earth's orbit, and parallel to it. Beta, Eta, Gamma and Spica, form the lower and longer side of a large spherical triangle whose vertex is in Beta.
164. Vindemiatrix, is a star of the 3d magnitude, in the right arm, or northern wing of Virgo, and is situated nearly in a straight line with, and midway between Coma Berenices and Spica Virginis. It is 19 S. W. of Arcturus, and about the same distance S. E. of Coma Berenices, and forms with these two a large triangle, pointing to the south. It bears also 18° S. S. E. of Denebola, and comes to the meridian about 23 minutes before Spica Virginis.
165. Zeta, is a star of the 3d magnitude, 114° N. of Spica, and very near the equinoctial. Gamma, situated near the left side, is also a star of the 3d magnitude, and very near the equinoctial. It is 13° due west of Zeta, with which and Spica it forms a handsome triangle. Eta, is a star of the 3d mágnitude in the southern wing, 5° W. of Gamma, and but 21° E. of the autumnal equinox.
The other stars in this figure may be easily traced by means of the map. About 13° E. of Spica, there are two stars of the 4th magnitude, 3° apart, which mark the foot of Virgo. These two stars are on nearly the same meridian with Arcturus, and culminate nearly at the same time. The lower one, marked Lambda, is on the south, and but 8° W. of the principal star in Libra. Several other stars of the 3d magnitude lie scattered about in this constellation, and may be traced out by the map.
ginis? Diamond? 162. Length of Virgo? Breadth? How may Spica be known? Note in fine print? 163. Describe Beta? What triangle? 164. Vindematrix ? 165. Zeta, Gamma and Eta ? What other stars and how found?
"Her lovely tresses glow with starry light;
According to the ancient poets, this constellation represents the Virgin Astræa, the goddess of justice, who lived upon the earth during the golden age; but being offended at the wickedness and impiety of mankind during the brazen and iron ages of the world, she returned to heaven, and was placed among the constellations of the zodiac, with a pair of scales (Libra) in one hand and a sword in the other.
Hesiod, who flourished nearly a thousand years before the birth of our Saviour, and later writers, mention four ages of the world; the golden, the silver, the brazen, and the iron age. In the beginning of things, say they, all men were happy, and all men were good; the earth brought forth her fruits without the labor of man; and cares, and wants, wars and diseases, were unknown. But this happy state of things did not last long. To the golden age, the silver age succeeded; to the silver the brazen; and to the brazen, the iron. Perpetual spring no longer reigned; men continually quarreled with each other; crime succeeded to crime; and blasphemy and murder stained the history of every day. In the golden age, the gods did not disdain to mix familiarly with the sons of men. The innocence, the integrity and brotherly love which they found among us, were a pleasing spectacle even to superior natures; but as mankind degenerated, one god after another deserted their late beloved haunts; Astræa lingered the last; but finding the earth steeped in human gore, she herself flew away to the celestial regions.
"Victa jacet pietas; et virgo cæde madentes
"Faith flees, and piety in exile mourns;
And justice here oppress'd, to heaven returns."
Some, however, maintain, that Erigone was changed into the constellation Virgo. The death of her father Icarus, an Athenian, who perished by the hands of some peasants, whom he had intoxicated with wine, caused a fit of despair, in which Erigone hung herself; and she was afterward, as it is said, placed among the signs of the zodiac. She was directed by her faithful dog Mæra to the place where her father was slain. The first bough on which she hung herself breaking, she sought a stronger, in order to effect her purpose.
"Thus once in Marathon's impervious wood,
When hastening to discharge her pious vows,
LEWIS' Statius, B. xi.
The famous zodiac of Dendera, as we have already noticed, commences with the sign Leo; but another zodiac, discovered among the ruins at Esne, in Egypt, commences with Virgo; and from this circumstance, some have argued, that the regular precession of the equinoxes established a date to this at least 2000 years older than that at Dendera. The discoveries of Champollion, however, render it probable that this ancient relic of astrology at Esne was erected during the reign of the Emperor Claudius, and consequently did not precede the one at Dendera more than fourteen years.
Of this, however, we may be certain: the autumnal equinox now corresponds with the first degree of Virgo; and, consequently, if we find a zodiac in which the summer solstice was placed where the autumnal equinox now is, that zodiac carries us back 90° on the ecliptic; this divided by the annual precision 504" must fix the date at about 6450 years ago. This computation, according to the chronology of the Sacred writings, carries us back to the earliest ages of the human species on earth, and proves, at least, that astronomy was among the first studies of mankind. The most rational way of accounting for this zodiac, says Jamieson, is to ascribe it to the family of Noah; or perhaps to the patriarch himself, who constructed it for the benefit of those who should live after the deluge, and who preserved it as a monument to perpetuate the actual state of the heavens immediately subsequent to the creation.
HISTORY.-Account of the poets? Hesiod's account? What other supposition? What zodiacs mentioned, and what calculations, &c.?
1. a VIRGINIS (Spica)-A splendid star with a minute companion; R. A. 18h. 16m. 47s.; Dec. S. 10° 19' 5". A 1, brilliant flushed white; B 10, bluish tinge.
2. B VIRGINIS (Zarijan)-A bright star with a small companion; R. A. 11h. 42m. 228.; Dec. N. 2° 40' 0". A 3%, pale yellow; B 11, light blue.
8. Y VIRGINIS-A fine BINARY STAR in the Virgin's right side; R. A. 12h. 83m. 88s.; Dec. S. 0° 34' 3". A 4, silvery white; B 4, pale yellow. A Binary System with a period of about 157 years. Map. VIII. Fig. 8.
4. d VIRGINIS-A star with a distant companion, on the left side, about 17° north-northwest of Spica, and nearly midway between y and & Virginis; R. A. 12h. 47m. 33s.; Dec. N. 4° 16' 1". A 8%, golden yellow; B 10%, reddish; several small stars in the field.
5. ε VIRGINIS (Vendemiatrix)—A star with a minute distant companion, on the upper extremity of the Virgin's left wing; R. A. 12h. 54m. 18s.; Dec. 11° 49′ 03′′. A 3%, bright yellow; B 15, intense blue. This last color on so small an object is very striking.
6. A TRIPLE STAR in the lower part of the southern wing, 7° northwest of Spica; R. A. 13h. 01m. 40s.; Dec. 8. 4° 41′ 0′′. A 4%, pale white; B 9, violet; C 10, dusky.
7. A LARGE, BUT RATHER PALE NEBULA, between Virgo's left wing and Leo's tail; R. A. 12h. 06m. 01s.; Dec. N. 15° 47' 02". About 6% from 6 Leonis, towards Arcturus, on the outskirts of a vast region of Nebula in the Virgin's wing. It is elongated in the direction of two telescopic stars.
8. A LONG PALE-WHITE NEBULA, among telescopic stars, on the upper part of the Vir. gin's left wing; R. A. 12h. 07m. 37s.; Dec. N. 14° 02′ 08′′. Situated one-third of the way from 3 Leonis to e Virginis, on the border of the vast nebulous region in Virgo. A curious object in the shape of a weaver's shuttle.
9. A LUCID WHITE ELLIPTICAL NEBULA, between the Virgin's right elbow and the Crow; R. A. 12h. 81m. 40s.; Dec. S. 10° 43′ 07". Map VIII., Fig. 45.
10. A DOUBLE NEBULA in the center of Virgo's left wing; R. A. 12h. 35m. 33s.; Dec. N. 12° 26' 01". It is 5° west of Vendemiatrix, toward Regulus, in a wonderful nebulous region. Map VIII., Fig. 46, shows it on the right, with two other nebulæ, and several stars in the figure.
11. A PALE ELLIPTICAL NEBULA, in the middle of the left wing; R. A. 12h. 44m. 50s., Dec. N. 12° 05′ 09". It looks like a paper kite, under an arch formed by three telescopic stars. Map. VIII., Fig. 47.
12. A WONDERFUL NEBULOUS REGION, about 2° from north to south, and 3° from east to west, is found on the left wing. It includes several of the objects described. For a drawing of this remarkable field, see Map VIII., Fig. 48.
CANES VENATICI (THE GREYHOUNDS).—MAP IV.
166. This modern constellation, embracing two in one, was made by Hevelius out of the unformed stars of the ancients which were scattered between Bootes on the east, and Ursa Major on the west, and between the handle of the Dipper on the north, and Coma Berenices on the south.
These Hounds are represented on the celestial sphere as being in pursuit of the Great Bear, which Bootes is hunting round the pole of heaven, while he holds in his hand the leash by which they are fastened together. The northern one is called Asterion, and the southern one, Chara.
TELESCOPIC OBJECTS.-Alpha? Beta? Gamma? Delta? Epsilon? What triple star? Nebula? Point out on the map.
166. Situation of Canes Venatici? By whom formed? How represented? Names of the hounds?
167. The stars in this group are considerably scattered, and are principally of the 5th and 6th magnitudes; of the twentyfive stars which it contains, there is but one sufficiently large to engage our attention. Cor Caroli or Charles' Heart, so named by Sir Charles Scarborough, in memory of King Charles the First, is a star of the 3d magnitude, in the neck of Chara, the southern Hound.
When on the meridian, Cor Caroli is 17° directly S. of Alioth, the third star in the handle of the Dipper, and is so nearly on the same meridian that it culminates only one minute and a half after it. This occurs on the 20th of May.
A line drawn from Cor Caroli through Alioth will lead to the N. polar star. This star may also be readily distinguished by its being in a straight line with, and midway between Benetnasch, the first star in the handle of the Dipper, and Coma Berenices; and also by the fact that when Cor Caroli is on the meridian, Denebola bears 28° S. W. and Arcturus 26° S. E. of it, forming with these two stars a very large triangle, whose vertex is at the north; it is also at the northern extremity of the large Diamond already described. The remaining stars in this constellation are too small and too much scattered to excite our interest.
1 A DOUBLE STAR near Chara's mouth; R. A. 12h. 08m. 06s.; Dec. N. 41° 33′ 01′′. A 6, yellow; B 9, blue. It is about 9° south of Cor Caroli, and one-third of the distance between that star and & Leonis. Map VIII., Fig. 10.
2. A MAGNIFICENT CLUSTER, between the southern Hound and the knee of Bootes; R. A. 13h. 34m. 45s. A splendid group, supposed to contain not less than 1,000 stars. Map VIII., Fig. 49.
3. A PAIR OF LUCID WHITE NEBULA, near the ear of the northern Hound; R. A. 18h. 23m. 06s.; Dec. N. 48° 01′ 07′′.
4. A LARGE BRIGHT NEBULA, 2° north by west of Cor Caroli; R. A. 12h. 43m. 22s.; Dec. N. 41° 59' 07". A fine pale-white object, compressed toward the center, and with several small stars in the field.
CONSTELLATIONS ON THE MERIDIAN IN JUNE.
BOOTES (THE BEAR DRIVER).—MAP IV.
168. THE BEAR-DRIVER is represented by the figure of a huntsman in a running posture, grasping a club in his right hand, and holding up in his left the leash of his two greyhounds, Asterion and Chara, with which he seems to be pursuing the Great Bear round the pole of the heavens. He is thence called Arctophylax, or the "Bear-Driver."
167. Describe the stars in this group? Cor Caroli?
TELESCOPIC OBJECTS.-What double star? Show on the map? Clusters? Point out on the map? Nebulæ ? 168. Describe Bootes? Why called the Bear-Driver?
169. This constellation is situated between Corona Borealis on the east, and Cor Caroli, or the Greyhounds, on the west. It contains fifty-four stars, including one of the 1st magnitude, seven of the 3d, and ten of the 4th. Its mean declination is 20° N., and its mean right ascension is 212°; its center is therefore on the meridian the 9th of June. It may be easily distinguished by the position and splendor of its principle star, Arcturus, which shines with a reddish luster, very much resembling that of the planet Mars.
170. Arcturus is a star of the 1st magnitude, situated near the left knee, 26° S. E. of Cor Caroli and Coma Berenices, with which it forms an elongated triangle, whose vertex is at Arcturus. It is 351° E. of Denebola, and nearly as far N. of Spica Virginis, and forms with these two, as has already been observed, a large equilateral triangle. It also makes, with Cor Caroli and Denebola, a large triangle whose vertex is in Cor Caroli.
A great variety of geometrical figures may be formed of the stars in this bright region of the skies. For example: Cor Caroli on the N., and Spica Virginis on the S., constitute the extreme points of a very large figure in the shape of a diamond; while Denebola on the W. and Arcturus on the E., limit the mean diameter at the other points.
171. Arcturus is supposed by some to be nearer the Earth than any other star in the northern hemisphere.
Five or six degrees S. W. of Arcturus are three stars of the 3d and 4th magnitudes, lying in a curved line, about 2° apart, and a little below the left knee of Bootes; and about 7° E. of Arcturus are three or four other stars of similar magnitude, situated in the other leg, making a larger curve N. and S.
172. Mirac, in the girdle, is a star of the 3d magnitude, 10° N. N. E. of Arcturus, and about 11° W. of Alphacca, a star in the Northern Crown. Seginus, in the west shoulder, is a star of the 3d magnitude, nearly 20° E. of Cor Caroli, and about the same distance N. of Arcturus, and forms with these two, a rightangled triangle, the right angle being at Seginus. The same star forms a right-angled triangle with Cor Caroli and Alioth, in Ursa Major, the right angle being at Cor Caroli.
173. Alkaturops, situated in the top of the club, is a star of the 4th magnitude, about 10° in an easterly direction from Seginus, which lies in the left shoulder; and about 41° S. of Alkaturops is another star of the 4th magnitude, in the club, near the east shoulder, marked Delta. Delta is about 9° distant from Mirac, and 74° from Alphacca, and forms, with these two, a regular triangle.
169. How situated? How many stars, and their magnitude? Declination? How distinguished? 170. Describe Arcturus, and its position? What triangles? What diamond? 171. Supposed nearness of Arcturus? 172. Describe Mirac and Seginus ? What triangles? 178. Situation and magnitude of Alkaturops? Of Delta?