mercredi 1 octobre 2008

Cepheus 10

α, 2.5, white.

Alderamin, from Al Deraimin of the Alfonsine Tables of 1521, originally was Al Dhirāʽ al Yamīn, the Right Arm, but it now marks that shoulder. Bayer wrote it "Aderaimin corrupte Alderamin"; Schickard, Adderoiaminon; Assemani, Alderal jemīn, while elsewhere we find Al Derab, Al Deraf, Alredaf, and Alredat. Kazwini mentioned it as Al Firḳ, but, although thus found on the Borgian globe, Ideler thinks it a mistake of that author, as a single star cannot represent a Flock, which Al Firḳ signifies. Ulug Beg more appropriately called α, β, and η Al Kawākib al Firḳ, the Stars of the Flock, although by this last word a Herd of Antelopes may be intended.
α culminates on the 27th of September.
It will be the Polaris of the year 7500; while midway between it and α Cygni lies the north polar point of the planet Mars.

β, Double, 3.3 and 8, white and blue.

Alfirk is now current for this star, although originally given to α; and Ficares is occasionally seen, from one of the degenerated names for the whole constellation that also may have been applied by the Arabs to others of its brighter stars.
The components are about 14ʺ apart, and the position angle is 251°.
γ, 3.5, yellow.

Errai of the Palermo and Er Rai of other catalogues, but sometimes Arrai, is from Al Rāiʽ, the Shepherd, a title indigenous to Arabia.
In China it was Shaou Wei, a Minor Guard.
γ now marks the left knee of the King, and will be the pole-star of 2600 years hence.
δ, ε, ν, and ζ, of about the 4th magnitude, were the Chinese Tsaou Foo, a charioteer of Mu Wang, the 5th emperor of the Chow dynasty, 536 B.C.
δ is a noted double, the yellow and blue components 41ʺ apart, at a position angle of 192°. The smaller is of the 7th magnitude, but the larger varies from 3.7 to 4.9 in a period of 10 2/3 days. This was discovered by Goodricke, John Goodricke of York, England, is still remembered in the astronomy of the last century as a diligent and successful observer of variable stars, although he was a deaf-mute and died at the early age of 22 years, in 1784; and Belopolsky thinks it a spectroscopic binary, the period of revolution equaling the period of variation.
From its neighborhood radiate the Cepheid meteors, visible from the 10th to the 28th of June.
Surrounding δ, ε, ζ, and λ, which mark the King's head, is a vacant space within the southern edge of the Milky Way similar to the Coal-sacks of the Northern and Southern Cross.
η and θ, 4th‑magnitude stars on and near the right wrist, mark Al Ḳidr.
κ, a double star, 4.4 and 8.5, is the Chinese Shang Wei, the Higher Guard. The components are yellow and blue, 7ʺ.5 apart, at a position angle of 124°.
μ, Irregularly variable, 4 (?) to 5 (?), garnet,

about 5° east of the head of Cepheus, is Sir William Herschel's celebrated Garnet Star, and so entered by Piazzi in the Palermo Catalogue, yet strangely omitted from Flamsteed's list, perhaps owing to its variability. This, suspected by Hind in 1848, was confirmed by Argelander.
It is one of the deepest-colored stars visible to the naked eye, and comparison with the near-by α will show its peculiar tint, which, however, sometimes changes to orange.
ξ, Binary, 4.5 and 7, blue.

Kazwini called this Al Ḳurḥaḥ, an Arabic word that Ideler translated as a white spot, or blaze, in the face of a horse; but thinking this not a proper stellar name, suggested Al Ḳirdah, the Ape. He seems here, however, to have forgotten Al Hiḳʽah of Orion,º of the same meaning as that to which he objected.
The components are 7ʺ apart, and their position angle is 285°.
ρ, a 5th‑magnitude, was Al Kalb al Rāʽi, the Shepherd's Dog, guarding the Flock shown by α, β, and η; k, h, and v, with others between the feet and Polaris, were Al Aghnām, the Sheep, apparently separated from the Flock.
υ1 and υ2, 5th‑magnitude stars, are given by Bayer, under the title Castula, as from Nonius, equivalent to Ταινία, the Front of the Garment, which they mark.
Sundry small members of this constellation and Camelopardalis were the Chinese Hwa Kae, the State Umbrella.

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