mercredi 1 octobre 2008

Eridanus 9

α, 0.4, white.

Achernar is from Al Āḣir al Nahr, the End of the River, nearly its present position in the constellation, about 32° from the south pole; but the p218title was first given to the star now lettered θ, the farthest in the Stream known by Arabian astronomers. For α Bayer had Acharnar pro Acharnahar vel Acharnarim, and Enar; Caesius, Acarnar; Riccioli, Acarnaharim and Acharnaar; Scaliger, Acharnarin; Schickard, Achironnahri; while Achenar and Archarnar are still occasionally used.
This star is supposed to be one of Dante's Tre Fascelle, notwithstanding its invisibility from Italy. Nowhere in Dante, neither in the Commedia nor in the minor works, does the word fascelle appear, at least according to the search engines at the Princeton Dante Project based on the respective editions reproduced there.
Chinese astronomers knew it as Shwuy Wei.
Ptolemy did not mention it, although he could have seen it from the latitude of Alexandria, 31°11ʹ, — a fact, among others, which argues that his catalogue was not based upon original observations, but drawn from the now lost catalogue of Hipparchos, compiled at Rhodes, more than 5° further north, from which place Achernar was not visible.
It culminates on the 4th of December, due south of Baten Kaitos.

β, 2.9, topaz yellow.

Cursa, 3° to the northwest of Rigel in Orion, is the principal star in this constellation, seen from the latitude of New York City.
The word is from Al Kursiyy al Jauzah, the Chair, or Footstool, of the Central One, i.e. Orion, formed by β, λ, and ψ Eridani with τ Orionis, and regarded as the support of his left foot; but in the earlier astronomy of the nomads it was one of Al Udḥā al Naʽām, the Ostrich's Nest, that some extended to ο1 and ο2.
The Century Cyclopedia gives Dhalim as an alternative title, undoubtedly from Al Ṭhalīm, the Ostrich; but, although used for β by several writers, this better belongs to θ.
The Chinese called β Yuh Tsing, the Golden Well.
γ1, 3, yellow.

Zaurac and Zaurak are from the Arabic Al Nāʼir al Zauraḳ, the Bright Star of the Boat; but Ideler applied this early designation to the star that now is α of our Phoenix.
With δ, ε, η, and others near, it made up the Chinese Tien Yuen, the Heavenly Park.

η, 3.7, pale yellow.

Azha is supposed to have been the Azḥā of Al Sufi, and the equivalent Ashiyane of the Persians, and was known by Kazwini as Al Udḥiyy, being p219chief among the stars of the Ostrich's Nest, which the word signifies. The other components were ζ, ρ, and σ; but this last, the 17th of Ptolemy, is not now to be identified in the sky, although it may be one of the three stars ρ displaced by proper motion since Ptolemy's time.
Near η, towards τ, are some other stars — ε and π Ceti among them — which in early days were included in the Nest, but later were set apart by Al Sufi as Al Sadr al Ḳetus, the Breast of the Whale.
θ, Double, 3 and 5.25.

Achernar was the early name for this at the then recognized end of the stream, Halley saying of it, ultima fluminis in veteri catalogo, referring to Tycho's work, of which his own was a supplement. Various forms of its title are given under α, but Acamar, from the Alfonsine Tables, is peculiar to θ.
Ulug Beg called it Al Ṭhalīm, the Ostrich, but Hyde rendered this the Dam, as if blocking the flow of the stream to the south.
Bullialdus, in his edition of Chrysococca's work, had it Αὖλαξ, the Furrow, equivalent to the sulcus used by Vergil to denote the track of a vessel, appropriate enough to a star situated in the Stream of Ocean; and Riccioli distinctly gave Sulcus for it in his Astronomia Reformata.
It is the solitary star visible from the latitude of New York City in early winter evenings, low down in the south, on the meridian with Menkar of the Whale; but Baily said that its brilliancy has probably lessened since Ptolemy's time, for the latter designated it by α — i.e. of the 1st magnitude.
Between it and Fomalhaut lie many small stars, not mentioned by Ptolemy, that Hyde said were Al Zibāl; but Al Sufi had already called them Al Riʼāl, the Little Ostriches.
ι, κ, φ, and χ, of about the 4th magnitude, were another Tien Yuen of the Chinese, different from that marked by γ; ι and κ are the lowest in the constellation visible from the latitude of New York.
μ and ω, 4th‑magnitude stars lying westward of β, were Kew Yew in China; Reeves including under this title b and the stars of the Sceptre.
ο1, 4.1, clear white.

In early Arabia this was Al Baīḍ, the Egg, from its peculiar white color, as well as from its position near the Ostrich's Nest. Modern lists generally write it Beid.
Situla, the Urn, also has been used for it, although there is no apparent applicability here, and the title is universally recognized for κ Aquarii.
ο2, Triple, 4, 9.1, and 10.8, orange and sky blue,

is the Keid of modern lists, Burritt's Kied, from Al Ḳaid, the Egg-shells, thrown out from the nest close by.
The Abbé Hell used it in the construction of his constellation Psalterium.
Its duplicity was discovered by Sir William Herschel in 1783, and in 1851 Otto Struve found the smaller star itself double and a binary of short period. The system is remarkable from its great proper motion of 4ʺ.1 annually. The two larger stars are 83ʺ apart, at a position angle of 108°, and the smaller 4ʺ apart, at an angle of 111°. The parallax by Elkin indicates a distance of twenty light years.
τ2, 4, yellow.

Angetenar of the Alfonsine Tables, now the common title, the Argentenar of Riccioli and Anchenetenar of Scaliger, is from Al Ḥināyat al Nahr, the Bend in the River, near which it lies; Ideler transcribing this as Al Anchat al Nahar. This is one of Bayer's nine stars of the same letter lying just above Fornax; he said of them, sibi mutuo succedentes novem.
See found, in 1897, a 14.9‑magnitude bluish star, about 52ʺ away, at a position angle of 128°.3.


mark another series of seven stars called in Bayer's text Beemim and Theemim. This last, used by Bode and now in current use, is perhaps the Arabic Al Tauʼamān and the Jews' Tĕōmīm, the Twins, from the pairs υ1, υ2, and υ3, υ4. Grotius thought it derived either from the foregoing or from an Arabic term for two medicinal roots; but Ideler's suggestion that it is from the Hebrew Bammaʼyim, In the Water, would seem more reasonable, although we have but few star-names from Judaea, and he intimated that it might be a distorted form of Al Ṭhalīm, the Ostrich. The Almagest of 1515 has Beemun; and the Standard Dictionary, The.eʽ.nim.

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