vendredi 26 septembre 2008

Pleiades 2

. . . the great and burning star,
Immeasurably old, immeasurably far,
Surging forth its silver flame
Through eternity, . . . Alcyone!
Archibald Lampman's Alcyone.
η, or Fl. 25, 3, greenish yellow.

Alcyone represents in the sky the Atlantid nymph who became the mother of Hyrieus by Poseidon; but, though now the Light of the Pleiades, its mythological original was by no means considered the most beautiful. Riccioli wrote the word Alcione and Alcinoe, and some early manuscripts have Altione.
The early Arabs called it Al Jauz, the Walnut; Al Jauzah or Al Wasaṭ, the Central One; and Al Naʼir, the Bright One; — all of Al Thurayya. The later Al Achsasi added to this list Thaur al Thurayya, which, literally the Bull of the Pleiades, i.e. the Leading One, probably was a current title in his day, for his Italian contemporary Riccioli said, in his Astronomia Reformata, that the lucida "Alcinoe" was Altorich non Athorric. Hipparchos has been supposed to allude to it in his ὀξύς, and ὀξύτατος, τῆς Πλειάδος, the Bright One, and the Brightest One, of the Pleiad. Yet, in the face of these epithets, Ptolemy apparently did not mention it in the Syntaxis; while Baily, in his edition of Hyde's translation of Ulug Beg's Tables, affixed Flamsteed's 25 and Bayer's η to the 32d star of Taurus, which is described as stella externa minuta vergiliarum, quae est ad latus boreale, our Atlas.
In Babylonia it determined the 4th ecliptic constellation, Temennu, the Foundation Stone.
In India it was the junction star of the nakshatras Krittikā and Rohinī, and individually Amba, the Mother; while Hewitt says that in earlier Hindu literature it was Arundhati, wedded to Vashishṭha, the chief of the Seven Sages, as her sisters were to the six other Rishis of Ursa Major; and that every newly married couple worshiped them on first entering their future home before they worshiped the pole-star. He thinks this a symbol of the prehistoric union of the northern and southern tribes of India.
We often see the assertion that our title is in no way connected with Ἀλκυών, the Halcyon, that "symbolic or mystical bird, early identified with the Kingfisher," the ornithological Alcedo or Ceryle; so that although the myth of the Halcyon Days, that "clement and temperate time, the nurse of the beautiful Halcyon,"
When birds of calm sit brooding on the charmed wave,
is not yet understood, some of Thompson's conjectures as to its stellar aspect will be found interesting. He writes that
the story originally referred to some astronomical phenomenon, probably in connexion with the Pleiades, of which constellation Alcyone is the principal star. In what appears to have been the most vigorous period of ancient astronomy (not later than 2000 B.C., but continuing long afterwards to influence legend and nomenclature) the sun rose at the vernal equinox, in conjunction with the Pleiad, in the sign Taurus: the Pleiad is in many languages associated with bird-names. . . and I am inclined to take the bird on the bull's back in coins of Eretria, Dicaea, and Thurii for the associated constellation of the Pleiad. . . Suidas definitely asserts that the Pleiades were called Ἀλκυόνες. At the winter solstice, in the same ancient epoch, the Pleiad culminated at nightfall in the mid-heaven. . . . This culmination, between three and four months after the heliacal rising of the Pleiad in Autumn, was, I conjecture, symbolized as the nesting of the Halcyon. Owing to the antiquity and corruption of the legend, it is impossible to hazard more than a conjecture; but that the phenomenon was in some form an astronomic one I have no doubt.
Mädler located in Alcyone the centre of the universe, but his theory has been shown to be fallacious. There is no satisfactory reason for his conclusion, and not much more for Miss Clerke's remarks as to the probable size and distance of Alcyone, — that it shines to its sister stars with eighty-three times the lustre of Sirius in terrestrial skies, while its intrinsic brilliancy, as compared with the sun, is 1000 times greater. All this rests upon the extremely doubtful assumption of a parallax of 0ʺ.013 deduced from the star's proper motion.
It culminates on the 31st of December.
The three little companions, easily visible with a low-power, form a beautiful triangle 3ʹ away from Alcyone.

Multi ante occasum Maiae coepere.
Vergil's 1st Georgic.

Fl. 20, or Bessel's c, 4.
Maia appears in the motto as personifying all the Pleiad stars, and the poet cautions the farmer against sowing his grain before the time of its setting.
She was the first-born and most beautiful of the sisters, and some have said that her star was the most luminous of the group; in fact, Riccioli, in his Almagestum Novum, distinctly wrote of Maia: dicta lucida Pleiadum & tertii honoris, quae mater Mercurii perhibetur, although in the Astronomia Reformata his "Alcinoe" is the lucida; so that we are uncertain which of these stars was the Pleias that he used for some one of the group. But the mythological importance of the goddess whose name Maia bears would indicate that Riccioli may have been correct as to the first of these identifications, and that the titles of the two stars perhaps should be interchanged.
The name also is written Mea and Maja, the feminine form of majus, an older form of magnus.d Cicero had the word Majja, calling the Pleiad sanctissima, for in his day Maia was only another figure for the great and much named Rhea-Cybele, Fauna, Faula, Fatua, Ops, familiarly known as Ma, or Maia Maiestas, the Bona Dea, or Great and Fruitful Mother, who gave name to the Roman month, our May.e
Ovid added to her title Pleias uda, the Moist Pleiad, as another symbol for the group; and Dante used her title for the planet Mercury, as the Atlantid was the mother of that god.
The equivalent Maou, for the Pleiades in China, is singularly like this the Latin word.
The nebula attached to this star, a part of the general nebulosity that envelops the group, was first noticed in 1882 on photographs by Pickering and the Messrs. Henry.

. . . the lost Pleiad seen no more below.
Byron's Beppo.

Fl. 17, or b, 4.6.
Electra, although for at least two or three centuries the title of a clearly visible star, has been regarded as the Lost Pleiad, from the legend that she withdrew her light in sorrow at witnessing the destruction of Ilium, which was founded by her son Dardanos, — as witness Ovid in the Fasti:
Electra Trojae spectare ruinas
Non tulit ante oculos, opposuitque manum;
or, as Hyginus wrote, left her place to be present at its fall, thence wandering off as a hair-star, or comet; or, reduced in brilliancy, settled down close to Mizar as Ἀλώπεξ, the Fox, the Arabs' Al Suhā, and our Alcor. In the Harleian Manuscript the word is written Electa.
Ovid called her Atlantis, personifying the family.
The Pirt-Kopan-noot tribe of Australia have a legend of a Lost Pleiad, making this the queen of the other six, beloved by their heavenly Crow, our Canopus, and who, carried away by him, never returned to her home.

Thy beauty shrouded by the heavy veil
Thy wedlock won.
Elizabeth Worthington Fiske.

Fl. 23, or d, 5, silvery white.
Merope often is considered the Lost Pleiad, because, having married a mortal, the crafty Sisyphus, she hid her face in shame when she thought of her sisters' alliances with the gods, and realized that she had thrown herself away. She seems, however, to have recovered her equanimity, being now much brighter than some of the others. The name itself signifies "Mortal."
This star is enveloped in a faintly extended, triangular, nebulous haze, visually discovered by Tempel in October, 1859; and there is a small, distinct nebula, discovered by Barnard in November, 1890, close by Merope, almost hidden in its radiance, although intrinsically very bright.
Taygete simul os terris ostendit honestum Pleias.
Vergil's 4th Georgic.

Fl. 19, or e, Double, 5.1 and 10, lucid white and violet.
Taygete, or Taygeta, a name famous in Spartan story for the mother of Lacedaemon by Zeus, was mentioned by Ovid and Vergil as another representative of this stellar family; the former calling it Soror Pleiadum, and the latter using it to fix the two seasons of the honey harvest, as in Davidson's translation of the passage beginning with our motto:
as soon as the Pleiad Taygete has displayed her comely face to the earth, and spurns with her foot the despised waters of the ocean; or when the same star, flying the constellation of the watery Fish, descends in sadness from the sky into the watery waves.
Ulug Beg applied to it Al Wasaṭ, the Central One, usually and more appropriately given to Alcyone.
Bayer lettered it q, describing it as Pleiadum minima; but the Century Cyclopaedia's ε is a misprint for e.

And is there glory from the heavens departed?
— Oh! void unmarkéd! — thy sisters of the sky
Still hold their place on high,
Though from its rank thine orb so long hath started,
Thou, that no more art seen of mortal eye.
Mrs. Hemans' The Lost Pleiad.

Fl. 16, or g, 6.5, silvery white.
Celaeno, or Celeno, has been called the Lost Pleiad, which Theon the Younger said was struck by lightning!
It gives but one half the light of Taygete; still it can be seen with the naked eye, if a good one, and is so given in the Heis Verzeichniss.

The Sister Stars that once were seven
Mourn for their missing mate in Heaven.
Alfred Austin.

Fl. 21 and Fl. 22, or k and l, 6.5 and 7.
Sterope I and Sterope II, less correctly Asterope, are a widely double star at the upper age of the rising cluster, and faintly visible only by reason of the combined light; so that Al Sufi's 5th magnitude seems large.
Ovid made use of Steropes sidus to symbolize the whole, but the present magnitudes would show that his star — if, indeed, he referred to any special star at all, as is improbable — was not ours, or else that a change in brilliancy has taken place. In fact, this also, and not without reason, has been called the Lost Pleiad.

Atlas, that on his brazen shoulders rolls
Yon heaven, the ancient mansion of the gods.
Potter's translation of Euripides' Ἴων.

Fl. 27, or f, Double, 4.5, intense white.
Atlas was Pater Atlas with Riccioli, apparently having been added to his day to the original group of the seven daughters. It was of him that Ovid wrote:
Pleiades incipiunt umeros relevare paternos;
for their setting relieved the father of some of his burden as bearer of the heavens.
With Pleione it marks the end of the handle of the Pleiad Dipper, and probably has a very minute, close companion, said to have been discovered by Struve in 1827, and again revealed, at an occultation by the moon, on the 6th of January, 1876.

Hinc sata Pleïone cum caelifero Atlante
Jungitur, ut fama est, Pleïadasque parit.
Ovid's Fasti.

Fl. 28, or h, 6.5.
Pleione, Riccioli's Mater Pleione, and Plione, were equally modern additions, although Valerius Flaccus used the word to personify the whole.
As the spectrum of this star shows the bright lines of hydrogen like that of P Cygni, Pickering suggests that it may similarly have had a temporary brilliancy and thus be the Lost Pleiad: a scientific and — if there has ever been in historic time a star in the cluster that is now missing — the most probable solution of this much discussed question; so that the mother seems to have been lost, as well as many of the daughters!
The Harleian Manuscript of Cicero's Aratos represents the Sisters by plain female heads under the title VII Pliades et Athlantides, and individually as Merope, Alcyone, Celaeno, Electra, Ta Ygete, Sterope, and Maia. Grotius has them in the same way, but in far more attractive style, from the old Leyden Manuscript, where we find the orthography Asterope and Mea, the former of which, appearing with Germanicus, has become common in our day. The German manuscript, dating from the 15th century, shows seven full-length figures, the Dark Sister smaller than the others, and wearing a dark-blue head-dress, the rest brighter in color, with faces of true German type.
While this list includes all the named Pleiad stars, some practically invisible without optical aid, yet every increase of power reveals a larger number. Riccioli wrote about this in 1651:
Telescopio autem spectatae visae sunt Galileo plus quam 40. ut narratur in Nuncio Sidereo;
a first-rate field-glass, taking in 3 1/4° and magnifying seven diameters, shows 57; Hooke, in 1664, saw 78 with the best telescope of his day; Swift sees 300 with his 4 1/2‑inch, and 600 with his 16‑inch; and Wolf catalogued, at the Paris Observatory in 1876, 625 in a space of 90ʹ by 135ʹ. But with the camera the Messrs. Henry photographed 1421 in 1885, and two years later, by a four-hours' exposure, 2326 down to the 16th magnitude within three square degrees, — more than are visible at any one time by the naked eye in the whole sky. And a recent photograph by Bailey, with the Bruce telescope, reveals 3972 stars in the region 2° square around Alcyone; although there is no certainty that all of those belong to the Pleiades group. Statements as to their magnitudes and distances make many of them exceed Sirius in size, and to be 250 light years away; but these are based upon an assumption of a parallax as yet only hypothetical. But, if correct, how appropriate are Young's verses in his Night Thoughts:
How distant some of these nocturnal Suns!
So distant (says the Sage) 'twere not absurd
To doubt, if Beams set out at Nature's Birth,
Are yet arrived at this so foreign World
Tho' nothing half so rapid as their Flight;
and Longfellow's stanza in his Ode to Charles Sumner:
Were a star quenched on high,
For ages would its light,
Still travelling downward from the sky,
Shine on our mortal sight.
While some of these undoubtedly are only optically connected with the true Pleiades, yet the larger part seem to form a more or less united group, which the spectroscope shows to be of the same general type; this fact being first brought out by Harvard observers in 1886, from comparisons of the spectra of forty of its stars. They are supposed to be drifting together toward the south-southwest, and so may be called a natural constellation.
Nicander wrote of them as ὀλίζωνας, "the smaller ones"; Manilius, as tertia forma, "the third-sized"; and many think that the light of some has decreased, not only from the legends of the Lost Pleiad and the fact that some of the sisters' names are applied to stars which could not possibly have been seen by the unaided eye, but also because only six are now visible to the average observer, and whoever can see seven can as readily see at least two more. Miss Airy counted twelve; Mr. Dawes, thirteen; and Kepler said that his scholar Michel Möstlin could distinguish fourteen, and had correctly mapped eleven before the invention of the telescope, while others have done about as well; indeed Carl von Littrow has seen sixteen. In the clear air of the tropic highlands more of the group are visible than to us in northern latitudes, — from the Harvard observing station at Arequipa, Peru, eleven being readily seen; so that Willis was unconsciously right in his verses:
the linked Pleiades
Undimm'd are three, though from the sister band
The fairest has gone down; and South away!
Smyth wrote:
If we admit the influence of variability at long periods, the seven in number may have been more distinct, so that while Homer and Attalus speak of six, Hipparchus and Aratus may properly mention seven.
Yet, we find Humboldt, in Cosmos, saying that Hipparchos refuted the assertion of Aratos that only six are to be seen with the naked eye, and that
One star escaped his attention, for when the eye is attentively fixed on this constellation, on a serene and moonless night, seven stars are visible.
But Aratos' words do not justify this statement as to his opinion. He wrote:
seven paths aloft men say they take,
Yet six alone are viewed by mortal eyes.
From Zeus' abode no star unknown is lost
Since first from birth we heard, but thus the tale is told;
this "seven paths," ἑπτάποροι, being first found in the ῾Ρήσος attributed to Euripides. Eratosthenes called it Πλειάς ἐπτάστερος, the Seven-starred Pleiad, although he described one as Παναφανής, All-invisible; Ovid repeated from the Phainomena the now trite
Quae septem dici, sex tamen esse solent;
and again:
Six only are visible, but the seventh is beneath the dark clouds.
Cicero thought of them in the same way, and Galileo wrote Dico autem sex, quando quidem septima fere nunquam apparet. But the early Copts knew them as Ἕξαστρον, the Six-starred Asterism, and many Hindu legends mention only six.
Discarding, of course, all the mythical explanations of the Lost Pleiad, I would notice some of the modern and serious attempts at an elucidation of the supposed phenomenon. Doctor Charles Anthon considered it founded solely upon the imagination, and not upon any accurate observation in antiquity. Jensen thinks that, as a favorite object in Babylonia, the astronomers of that country attached to it, with no regard to exactitude, their number of perfection or completeness, 7 playing with them a more important part even than it did among the Jews; thence it descended to Greece, where, its origin being lost sight of, was caused the discrepancy which we cannot now explain, as well as the legends and folk-lore on the subject. Lamb asserted that the astronomers of Assyria could see in their sky seven stars in the group, and so described them; but the Greeks, less favorably situated, finding only six, invented the story of the missing sister. Riccioli propounded a theory — which I have nowhere found adopted by any later writer — that the seventh and missing Pleiad may have been a nova appearing before that number was recorded by observers, but extinguished about the date of the Trojan war; this last idea accounting, too, for the association of Electra with the lost one. Still another explanation is hinted at by Thompson under Coma Berenices; and the really scientific theories of Smyth and Pickering have already been noticed. It is in these last two, I think, that the solution of this interesting question will be found, if at all; and with the astronomers I would leave it, as perhaps I ought to have done before.
Ptolemy mentioned Πλειάς for only four stars in Ταῦρος that Baily said were Flamsteed's 18, 19, 23, and 27, our Alcyone singularly being disregarded, as well as four others of our named stars; and Al Sufi, who revised Ptolemy's observations, stated that this "Alexandrian Quartette" also were the brightest in his day — the 10th century. But Ulug Beg, although he is supposed to have followed Ptolemy, applied "Al Thurayya" to the five that Baily said were Fl. 19, 23, 21, 22, and 25 (Alcyone). Baily himself, editing Hyde's translation of Ulug Beg, gave only Fl. 19 and 23 as of "Al Thuraja."
Recent photographic observations have revealed other nebulous matter, in different degrees of condensation, scattered throughout the cluster, connecting its various members; while Barnard in 1894 found vast nebulosity extending almost as far as ζ Persei.
The Pleiades afford so convincing a proof of the popular misapprehension as to the moon's apparent magnitude that I am tempted to introduce another illustration drawn from these stars. The angular distance between Alcyone and Electra and between Merope and Taygeta is greater by several minutes than the mean angular diameter of the moon's disc, — 31ʹ7ʺ, — so that the latter could be inserted within the quadrangle formed by those four stars with plenty of room to spare; although in looking at the cluster the impression is that our satellite would cover the whole. An occultation of the Pleiades by the moon gives a vivid realization of this fact; and as this is a not infrequent phenomenon, I commend its observation to any unbeliever.

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