mardi 23 septembre 2008

Perseus 9

It is in the church of this Saint Laurence at Upton that the remains of Sir William Herschel lie buried, and over them is the fitting inscription:
Coelorum perrupit claustra.

Tintoretto's celebrated painting of the hero's exploit now hangs in the Hermitage Gallery of Saint Petersburg.

We are indebted to the Talmudists for this story, which probably originated in Babylonia; and they added that, after Adam had separated from Līlīth and their demon children, Eve was created for him. Our Authorized Version renders the original word, in Isaiah xxxiv.14, by "screech owl"; the Revised Version, by "night-monster"; Cheyne adopts the Hebrew Lilith in the Polychrome Bible; and Luther's Bible had Kobold, but this corresponded to the Scottish Brownie and the English "Robin Goodfellow," — Shakespeare's "Puck." Saint Jerome's Vulgate translated it "Lamia," the Greek and Roman title for the fabled woman, beautiful above, but a serpent below, that Keats reproduced in his Lamia.

α, 2.1, brilliant lilac and ashy.
Algenib, with the early variations of Algeneb, Elgenab, Genib, Chenib, and Alchemb, is from Al Janb, the Side, its present position on the maps; Chrysococca similarly called it Πλευρά Περσάους.
Another name, Marfak or Mirfak, the Elbow, sometimes written Mirzac, comes from the Arabians' Marfiḳ al Thurayya, thus qualified as being next to the Pleiades to distinguish it from the other elbow. But this may indicate a different representation of Perseus in their day, — a suspicion strengthenedº by the nomenclature of others of his stars, especially of ξ and ο.
Assemani alluded to a title on the Borgian globe, — Mughammid, or Muliammir, al Thurayya, the Concealer of the Pleiades, — which, from its location, may be for this star.
With γ, δ, and others it was the Chinese Tien Yuen, the Heavenly Enclosure.
Algenib never sets in the latitude of New York City, but just touches the horizon at its lower culmination. Its spectrum is of Secchi's second, or Solar, type, and the Potsdam observations indicate that the star is approaching our system at the rate of 6 1/2 miles a second.
the Gorgon's Head, a ghastly sight,
Deformed and dreadful, and a sign of woe.
Bryant's translation of the Iliad.

β, Spectroscopic binary and variable, 2.3 to 3.5, white.
Algol, the Demon, the Demon Star, and the Blinking Demon, from the Arabians' Raʼs al Ghul, the Demon's Head, is said to have been thus called from its rapid and wonderful variations; but I find no evidence of this, and that people probably took the title from Ptolemy. Al Ghul literally signifies a Mischief-maker, and the name still appears in the Ghoul of the Arabian Nights and of our day. It degenerated into the Alove often used some centuries ago for this star.
Ptolemy catalogued it as τῶν ἐν γοργονίῳº ὁ λαμπρός, "the bright one of those in the Gorgon's head," which Al Tizini followed in his Nāʼir, for, with π, ρ, and ω, it made up that well-known group, itself being the Gorgonea prima; the Γοργόνιον of Chrysococca, Gorgoneum Caput of Vitruvius [IX.4.2], Caput Gorgonis of Hyginus, and the Gorgonis Ora of Manilius.
With astronomical writers of three centuries ago Algol was Caput Larvae, the Spectre's Head. Hipparchos and Pliny made a separate constellation of the Gorgon stars as the Head of Medusa, this descending almost to our own day, although always connected with Perseus.
The Hebrews knew Algol as Rōsh ha Sāṭān, Satan's Head, Chilmead's Rosch hassatan, the Divels head; but also as Līlīth, Adam's legendary first wife,2 the nocturnal vampire from the lower world that reappeared in the demonology of the Middle Ages as the witch Lilis, one of the characters in Goethe's Walpurgis Nacht.
The Chinese gave it the gruesome title Tseih She, the Piled-up Corpses.
Astrologers of course said that it was the most unfortunate, violent, and dangerous star in the heavens, and it certainly has been one of the best observed, as the most noteworthy variable in the northern sky. It "continues sensibly constant at 2.3 magnitude during 2 1/2 days, then decreases, at first gradually, and afterward with increasing rapidity, to 3.5 magnitude"; its light oscillations occupying about nine hours; its total period being stated as 2 days 20 hours 48 minutes 55 seconds. Al Sufi, a good observer for his day, yet strangely making no allusion to its variability, called it a 2nd‑magnitude; and the phenomenon was first scientifically noted by Montanari during several years preceding 1672. This was confirmed by Maraldi's observations of 1694, and, later, by those of the Saxon farmer Palitsch,3 but its approximate period seems to have been first announced by Goodricke in 1782, who even then advanced the theory of a dark companion revolving around it with immense velocity, which periodically cut off its light. This, reaffirmed by Pickering in 1880, was made certain by the spectroscope in the hands of Vogel of Potsdam in 1889. Chandler thinks that there must exist another invisible body larger than either Algol or its companion, around which both revolve in a period of 130 years; but Tisserand has shown that the phenomenon on which Chandler bases this opinion can be explained in a different and simpler way. Its name is used for the type indicating short-period variables whose changes may be explained by this theory of "eclipses." Of these seventeen are now known.
Although classed among the white stars with a Sirian spectrum, Al Sufi wrote of it as red, which Schmidt confirmed as seen by him at Athens for a short time in 1841. It seems to be approaching us at the rate of about a mile a second; and is estimated as a little more than a million miles in diameter.
When on the meridian Algol is almost exactly in the zenith of New York City. This is at nine o'clock in the evening of the 23d of December.

ε, Double, 3.5 and 9, greenish white and lilac.
In China this, with the 4th‑magnitude ν and some others, was Keuen She.
It has been suspected of variation in color as well as in light. The components are about 9ʺ apart, at a position angle of 10°, and form an interesting object for a four-inch telescope.
p334 η, Double, 5 and 8.5, orange and smalt blue,
is unnamed except in China, where, with γ, it was Tien Chuen, Heaven's Ship. But it is noticeable in having three small stars on one side nearly in line, and one on the other, forming a miniature representation of Jupiter and his satellites. The components are 28ʺ apart, at a position angle of 300°.

λ and μ, 4th- to 5th‑magnitude stars, were Tseih Shwuy, Piled-up Waters.
ξ, a 4 1/2‑magnitude, is the Menkib of Burritt, from Mankib al Thurayya, the Shoulder of — i.e. next to — the Pleiades in the Arabian figure, although on modern charts it marks the left ankle.

π, a double star of 4th and 9th magnitudes, is Ati and Atik, from the word Al ʽĀtiḳ found on the Borgian globe, at the space between the shoulders, and applied to it by Ulug Beg; but it is now located near the left foot.

π, a 4 1/2‑magnitude, was Gorgonea secunda; and ρ, a variable from 3.4 to 4.2, orange in color, was Gorgonea tertia.

τ, a 4 1/2‑magnitude, with others in the constellation, was known by the Chinese as Ta Ling, the Great Mound.

υ, 3.8,
marking the tip of the weapon in Perseus' hand, bears many titles with Bayer, all referring to its location; but none of these — indeed, no name at all — is seen in modern lists. Bayer wrote of them:
In falce adamanthinā trium praecedens. Falx dicitur & curvus Harpes, Gladius falcatus, & incurvus, Arab. Nembus, Maroni Ensis falcatus, & curvus Saturni dens.
The "Arab." would seem erroneous, for Nembus is neither Arabic nor Latin, and if intended for Nimbus, is equally wrong, as there is no suspicion of nebulosity about the star. Curvus Saturni dens was Vergil's designation in the Georgics [II.406] for a "pruning-hook," and the equivalent of Falx and Ἅρπη, so well known in connection with Perseus.
χ, a multiple star, and the little h mark two clusters noticeable with the naked eye, Nos. 884 and 869 of the New General Catalogue, 30ʹ and 15ʹ in diameter, almost connected, and apparently a protuberant part of the Milky Way. They were the Arabians' Miʽṣam al Thurayya, the Wrist of — i.e. next to — the Pleiades.
Hipparchos seems to have been the first to record them, which he did as νεφελοειδής, a "cloudy spot"; Ptolemy, as συστροφή, a "dense mass"; and subsequent astronomers down to Galileo's day similarly considered them nebulous. The Alfonsine Tables said, revolutio nebulosa, and the Almagest of 1551, girus ille in capulo ensis, this girus — correctly gyrus — signifying a circle. They seem strangely to have escaped the notice of astrologers, who, as a rule, devoted much attention to clusters as harmful objects which portended accidents to sight and blindness.
In China they were Foo Shay.
These stars and clusters are now known as the Sword Hand of Perseus, i, g, φ, and υ marking the outstretched sword. In small telescopes the twin clusters form one of the most beautiful objects within their reach.
Between χ and η lies the diverging point of the Perseids, the prominent meteor stream visible from the 19th of July to the 17th of August, its maximum occurring about the 10th of the latter month and continuing several days. These appear in the early part of the night, at an elevation of from fifty-six to seventy miles, moving with moderate speed and leaving streaks of yellow light; the radiant advancing nearly 30° eastward during their period of visibility. Schiaparelli found their orbit coincident with that of Tuttle's comet, III of 1862. The Perseids were recorded as far back as 811, seven appearances being mentioned down to 841, and they are supposed to have been members of the solar system for thousands of years, although now, perhaps, steadily decreasing in number. Dante may have made reference to them in the Purgatorio [V.37‑39]:
Vapors enkindled saw I ne'er so swiftly
At early nightfall cleave the air serene,
Nor, at the set of sun, the clouds of August;
and in the later Middle Ages they were known as the Larmes de Saint Laurent,c Saint Laurence's4 Tears, his martyrdom upon the red-hot gridiron having taken place on the 10th of August, 258.

ω, of the 5th magnitude, was Gorgonea quarta.

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