mercredi 1 octobre 2008

Andromeda 14

δ, Double, 3 and 12.5, orange and dusky.

Burritt added to the letter for this the title Delta, perhaps from its forming a triangle with ε and a small adjacent star.
It marks the radiant point of the Andromedes I of the 21st of July.
The components are 27ʺ.9 apart, at a position angle of 299°.3.
θ, a 4.7‑magnitude star, with ρ and σ, was the Chinese Tien Ke, The star-names of China that appear in this work are few in comparison with the total in the great number of that country's constellations. I occasionally cite them merely to indicate the general character of Chinese stellar nomenclature the Heavenly Stable.

ξ, 4.9,

is Adhil, first appearing in the Almagest of 1515, and again in the Alfonsine Tables of 1521, from Al Dhail, the Train of a Garment, the Arabic equivalent of Ptolemy's σύρμα; but Baily thought the title better applied to the slightly fainter A, which is more nearly in that part of the lady's dress; and p39Bayer erroneously gave it to the 6th‑magnitude b, claiming — for he was somewhat of an astrologer, although the Os Protestantium of his day — that, with the surrounding stars, it partook of the nature of Venus.

φ, Binary, 4.9 and 6.5, yellow and green, and χ, 5,

in Chinese astronomy, were Keun Nan Mun, the Camp's South Gate; they lie in the train near the star σύρμα. The components of φ were observed by Burnham in 1879, 0ʺ.3 apart, at a position angle of 272°.4.

NGC 224, or 31 M.,

the Great Nebula, the Queen of the Nebulae, just northwest of the star ν, is said to have been known as far back as A.D. 905; was described by Al Sufi as the Little Cloud before 986; and appeared on a Dutch star-map of 1500. But otherwise there seems to be no record of it till the time of Simon Marius (Mayer of Gunzenhausen), who, in his rare work De Mundo Joviali, tells us that he first examined it with a telescope on the 15th of December, 1612. He did not, however, claim it as a new discovery, as he is reported to have fraudulently done of the four satellites of Jupiter,This planet was known to the Greeks as Ζεύς, and as Φαέθων, the Shining One. , when he gave them their present but rarely used names, Io, Europa, Ganymede, and Kallisto, that are now known as I, II, III, and IIII, in the order of their distances from the planet. Halley, however, did so claim it in 1661 in favor of Bullialdus (Ismail Bouillaud), who, although he doubtless again brought it into notice as the nebulosa in cingulo Andromedae, expressly mentioned that it had been observed 150 years previously by some anonymous but expert astronomer.
Hevelius catalogued it in his Prodromus, and Flamsteed inserted it in his Historia as nebulosa supra cingulum and nebulosa cinguli; but Hipparchos, Ptolemy, Ulug Beg, Tycho Brahē, and Bayer did not allude to it, from which some have inferred an increase, or variability, in its light; but there is no positive evidence as to this, and it does not seem probable.
Marius said that it resembled the diluted light from the flame of a candle seen through horn, This reminds us of Dante's beautiful simile in the Paradiso, although of a different object:
So that fire seemed it behind alabaster, while others of our early astronomers described it differently; discordances probably owing to the different means employed. Its true character seems as yet undetermined, although astro-photography p40"has proved it to be a vast Saturniform body, a great, comparatively condensed nucleus, surrounded by a series of rings, elliptical as they appear to us, but probably only so from the angle under which they are presented to our view"; "masses of nebulous matter partially condensed into the solid form" — a new and enormous solar system in formation.
Its length, or diameter, about 3½°, is estimated at more than thirty thousand times the distance from the earth to the sun.
Its attendant companion, visible as a nebula in the same field if a low-power be used, is the star-cluster, discovered in 1749 by Le Gentil. It is nearly circular in form, and apparently, 1/8 the size of the Great Nebula. Sir William Huggins and others have suggested that the small nebulae near the latter may be planets in process of formation.
S Andromedae, the nova of 1885 that excited so much interest, was first seen about the middle of August, 16″ of arc to the southeast of the nucleus, and, for a brief period, of the 6th to the 7th magnitude; but it soon disappeared to ordinary glasses, and Hall last saw it with the 26‑inch refractor at Washington on the 1st of February, 1886, as of the 16th magnitude.

Aucun commentaire: