“Dixit et antiqui monumenta perennia facti
Anguis, Avis, Crater sidera, juncta micunt.”
The star α Crateris was rated 4th magnitude by Al-Sufi and all other observers, and the Harvard measures make it 4·20, a satisfactory agreement. It has three companions noted by Admiral Smyth. One of these he called “intense blood colour.” This is R Crateris, now known to be variable from above the 8th magnitude to below the 9th. Sir John Herschel called it an “intense scarlet star, a curious colour.” With 3-inch refractor in the Punjab I found it “full scarlet.” It is one of an open pair, the further of the two from α. There is a third star about 9th magnitude a little south of it. Ward saw a 13th magnitude star between α and R with a 2⅞-inch (Wray) refractor. This I saw “readily” with my 3-inch. Smyth does not mention this faint star, although he used a much larger telescope.
Corvus, the Crow, is a small constellation, north of Hydra. Aratus says “the Crow form seems to peck the fold of the water snake” (Hydra). The victory which Valerius Corvinus is said to have owed to a crow has given it the name of Pomptina, because the victory took place near the Pontine marshes.[446] A quadrilateral figure is formed by its four brightest stars, γ, δ, β, and ε Corvi. This figure has sometimes been mistaken for the Southern Cross by those who are not familiar with the heavens. But the stars of the Southern Cross are much brighter.
The constellation Centaurus, the Centaur, lies south of Hydra and Libra, and north of the Southern Cross. According to Dupuis, Centaurus represents the 3rd “labour of Hercules,” his triumph over the Centaurs.[447] The Centaurs were supposed to be a people living in the vicinity of Mount Ossa, who first rode on horses. The constellation was also called Semivir, Chiron, Phobos, Minotaurus, etc. Al-Sufi says it “is represented by the figure of an animal, of which the forepart is the upper part of a man from the head to end of the back, and its hinder part is the hinder part of a horse, from the beginning of the back to the tail. It is to the south of the Balance [Libra] turning its face towards the east, and the hinder part of the beast towards the west.”
Al-Sufi describes very clearly the four bright stars of the famous “Southern Cross.” Owing to precession these stars were some 7° further north in the tenth century than they are at present, and they could have been all seen by Al-Sufi, when on the meridian. In the time of Ptolemy and Hipparchus, they were still further north, and about 5000 years ago they were visible in the latitude of London. Dante speaks of these four stars as emblematical of the four cardinal virtues, Justice, Temperance, Fortitude, and Prudence.
Closely south-east of α and β Crucis is the dark spot in the Milky Way known as the “Coal Sack,” which forms such a conspicuous object near the Southern Cross. It was first described by Pinzon in 1499; and afterwards by Lacaille in 1755. Although to the naked eye apparently black, photographs show that it contains many faint stars, but, of course, much less numerous than in the surrounding regions. The dark effect is chiefly caused by contrast with the brilliancy of the Milky Way surrounding it.
Al-Sufi also mentions the bright stars α and β Centauri which follow the Southern Cross. He says that the distance between them “is four cubits,” that is about 9° 20′, but it is less than this now. α has a large “proper motion” of 3″·67 per annum, and was farther from β in Al-Sufi’s time than it is at present. This, however, would not wholly account for the difference, and Al-Sufi’s over-estimate is probably due to the well-known effect by which the distance between two stars is apparently increased when they are near the horizon. Several of Al-Sufi’s distances between southern stars are over-estimated, probably for the same reason.
The constellation Lupus, the Wolf, is south of Libra and Scorpio. It lies along the western border of the Milky Way. According to ancient writers it represents Lycaon, King of Arcadia, a contemporary of Cecrops, who is said to have sacrificed human victims, and on account of his cruelty was changed into a wolf. Another fable is that it represents a wolf sacrificed by the Centaur Chiron. According to Brown, Lupus appears on the Euphratian planisphere discovered by George Smyth in the palace of Sennacherib. Al-Sufi called it al-sabu, “the Wild Beast.” It was also called al-fand, “the Leopard,” and al-asada, “the Lioness.”
Ara, the Altar, lies south of Scorpio. According to ancient writers it represents an altar built by Vulcan, when the gods made war against the Titans. It is called by Al-Sufi al-midjman, “the Scent Box,” or “the Altar.”
The little constellation Corona Australis, the Southern Crown, lies south and west of Sagittarius, east of Scorpio, and west of Telescopium. Aratus refers to the stars in Corona Australis as—