dimanche 5 octobre 2008

Pegasus 9

Brugsch mentions as in its location an Egyptian constellation, the Servant; and some of its stars would seem to be shown on the Denderah planisphere as a Jackal.
The Arabs knew the familiar quadrangle as Al Dalw, the Water-bucket, the Amphora of some Latin imitator, which generally was used for the Urn in Aquarius; and the Arabian astronomers followed Ptolemy in Al Faras al Thānī, the Second Horse, which Bayer turned into Alpheras; Chilmead, into Alfaras Alathem; and La Lande, into Alpharès.
Argelander catalogued 108 stars here, down to the 6th magnitude; and Heis, 178, to the 6 1/2.
The starless region toward Pisces was Al Bīrūnī's Al Baldah, the Fox's Kennel, a term for whose stellar connection I find no explanation.
Before leaving this constellation, it is worth while to note that an asterism, now virtually lost to us and seldom mentioned except in the lists of Al Sufi, Al Amasch, and Kazwini, is described by the last-named under the title Al Faras al Tamm, the Complete Horse. Although somewhat indefinitely marked out, it is said to have occupied the space between the eastern wing of the Swan, the chest of Pegasus, Equuleus, and the tail of Lacerta, drawing for its components from the last three; but Beigel held that it could have existed only with the grammarians, — the Tāmm in its title being easily confused, in transcription, with the Thānī in the Arabians' name for Pegasus. Ideler's Sternnamen is the sole modern work in which I find any reference to this Complete Horse, and even that author, in one passage, seems to regard Monoceros as the modern representative of this somewhat mythical constellation; but this is impossible if Kazwini's description be accepted. Indeed, Ideler himself, later on in his book, changed his opinion to agree with that of Beigel.
α, 2.5, white.

Markab — Flamsteed's Marchab — is the Arabs' word for a Saddle, Ship, or Vehicle, — anything ridden upon, — that was early applied to this star; but they also designated it at Matn al Faras, the Horse's Withers or Shoulder, and Bayer cited Yed Alpheras, the Horse's Hand, or, more properly, Forearm, — the Arabian Yad. Kazwini knew it and β as Al ʽArḳuwah, the Cross-bar of the well in which Al Dalw, the Bucket, was used.
In India it was noted as the junction star of the Bhādra-padā nakshatras, detailed under β.
p325 In China it was Shih, a title borrowed from the sieu that it marked.
Brown thinks that, with γ and ζ, it was the Euphratean asterism Lik‑bar‑ra, the Hyaena, — perhaps Ur‑bar‑ra.
Among astrologers it portended danger to life from cuts, or stabs, and fire. It culminates on the 3d of November, and when on the meridian forms, with γ, the southern side of the Great Square, β and δ forming the northern, and all 15° to 18° apart.
Markab's spectrum is Sirian, and it is receding from us at the rate of three quarters of a mile a second.
β, Irregularly variable, 2.2 to 2.7, deep yellow.

This is the Scheat of Tycho, the Palermo Catalogue, and modern lists generally, either from Al Sāʽid, the Upper Part of the Arm, or, as Hyde suggested, from the early Saʽd, appearing in the subsequent three pairs of stars. Bayer had Seat Alpheras; Chilmead, Seat Alfaras; Riccioli, Scheat Alpheraz; and Schickard, Saidol-pharazi.
Arabian astronomers knew it as Mankib al Faras, the Horse's Shoulder, mentioned by Ulug Beg and still occasionally seen as Menkib. Chilmead had Almenkeb.
The Great Square, of which β formed one corner, constituted the double asterism, the 24th and 25th nakshatras, Pūrva, Former, and Uttara, Latter, Bhādra-padā, Beautiful, Auspicious, or Happy Feet, sometimes also called Proshtha-padā, Proshtha meaning a Carp or Ox; but Professor Whitney translated it "Footstool Feet," and said that the authorities do not agree as to the figures by which they are represented, for by some the one, by others the other, is called a Couch or Bed, the alternate one, in either case, being pronounced a Bifaced Figure, or Twins. This Couch is not an inapt representation of the group if both asterisms are taken together, the four stars well marking the feet. Weber calls them Pratishṭhana, a Stand or Support, as Whitney wrote,
an evident allusion to the disposition of the four bright stars which compose it, like the four feet of a stand, table, bedstead, or the like;
the regents of these nakshatras being Augusta Ekapāt, the One-footed Goat, and Ahi Budhya, the Bottom Snake, "two mythical figures, of obscure significance, from the Vedic Pantheon." The 24th manzil, formed by α and β, was Al Fargh al Muḳdim, the Fore Spout, i.e. of the water-bucket, — Al Bīrūnī's Al Fargh al Awwal, the First, or the Upper, Spout; and the 24th sieu was these same stars known as Ying She, or Shih, a House, anciently Sal and Shat; but it also comprised parts of Aquarius and Capricornus. They also were the Persian Vaht, the Sogdian and Khorasmian Farshat Bath, and the Coptic Artulos, all signifying something pertaining to Water; while in astrology β indicated danger to mankind from that element.
Within the area of this Square Argelander counted only about 30 naked-eye stars, but in the clearer sky of Athens Schmidt saw 102.
It was in the 24th sieu that the Chinese record a conjunction of the planets Mercury, Mars, Jupiter, and Saturn, on the 28th of February, 2449 B.C., according to Bailly's computations; but we sometimes see this statement made as to five planets, Venus being added, and as having taken place on the 29th of February, that year being bissextile. Smyth indefinitely mentions this conjunction as at some point between α Arietis and the Pleiades; Flammarion states that it was in Capricorn; and Steele alludes to it as of 2246 B.C., and between the tenth and eighteenth degrees of Pisces. At that date the signs and constellations were about coincident.
The variability of β was discovered by Schmidt in 1847, and Argelander found a period of forty-one days; but Schoenfeld thinks that irregular oscillations, in a period of thirty to fifty days, are more probable.
The spectrum of Scheat is of the third type of Secchi's classification, which includes the red and orange stars and most of the variables: "α Orionis, α Herculis, Antares, and ο Ceti (Mira) are good examples."
The star is receding from us about four miles a second.
It is one of the so‑called lunar stars, much observed in navigation.
γ, 3, white,

erroneously placed by Tycho in Pisces, marks the extreme tip of the Horse's wing, so that its name Algenib has been considered as derived from Al Janāḥ, the Wing, but it probably is from Al Janb, the Side. It has sometimes been written Algemo. Al Bīrūnī quoted it, with δ (α Andromedae), as Al Fargh al Thānī, the Second, or Lower, Spout, i.e. of the Bucket. This also is the title of the 25th manzil, but appears in Professor Whitney's list as Al Fargh al Muʼḥir, the Rear Spout, and in Smyth's as Al Fargu.
Chrysococca called it Πήγασος from the constellation.
Reeves said that it is the Chinese Peih, a Wall or Partition, thus taking the title of the 25th sieu, which it marked and, with δ, constituted. It lies at the junction of the nakshatras Bhādrapadā and Revatī; and, with δ, was included in the corresponding lunar station of several other nations.
With the same star and β Cassiopeiae it makes up the Three Guides, all these being almost exactly on the prime meridian, the vernal equinox lying in a starless region of Pisces about 15° south of γ Pegasi. Two 11th‑magnitude stars are close by.

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