IN STARRY SKIES

Evening Post, Volume CXIII, Issue 110, 11 May 1932, Page 3

IN STARRY SKIES

A KEY TO THE CONSTEL-

LATIONS

No. X. (By "Omega Oentauri.")

At all the times indicated on this map the eighteenth hour of right ascension is due north and the sixth hour duo south of the Pole. A portion of Puppis and the whole of Malus havo now disappeared in the south-west. A considerable part of the. long line which marks the body of Hydra has also gone. Crater the Cup which rests so strangely on the coils of the Snake is in the act of sotting. Part of the Virgin has sunk below the horizon in the west, and a similar part of Bootes in the north-west. The Lion, Coma Berenices, and Canes Venatici, which in the last map appear below the Virgin and the Herdsman, have now completely disappeared. On the other hand, portions of Eridanus, Toucan, Cetus, Pisces, Pegasus, and Cygnns have come into view along the eastern horizon, whilst Sculptor, Aquarius, Equuleus, Delphinus, and Lyra, which were just rising at the time, of the last map, are now well up. Facing due north wo see that Hercules has passed the meridian and that Lyra is approaching it. Vega, the chief star of the latter constellation, is sur-

passed in apparent brightness by Sirius, Canopus, and Alpha Centauri only. Strange to say, Beta Lyrae, though three and a half magnitudes fainter j than Alpha, 'is in reality a far more brilliant sun. It is about 125 times as far away. Vega is a hundred times as brilliant as our sun, but Beta Lyrae is 750 times as bright as Vega. More than half-way from the horizon towards the zenith Ophiuchus has just passed the meridian and is now being followed by the end coils and tail of the Serpent.. The bright quadrilaterals of Sagittarius aro close to the zenith. The heads of Ophiuchus and Hercules are close beside one another, though the bodies extend in opposite directions. Alpha Ophiuchi is only a second magnitude, and Alpha Herculis a third magnitude star. But.the former is 67 light years away, and the latter over threo thousand. So in . reality Alpha Ophiuehi is as bright as Vega ana Alpha Herculis a little brighter than Beta" Lyrae, or more than ninety thousand times as bright as our sun. Facing the north-east, the long neck of the Swan now stretches upwards, whilst.the -wings are spread along the horizon. The bright star Deneb has not yet risen. Above the Swan we see the tiny constellations the Arrow and the Dolphin, and a little higher still the Eagle. The most noticeable feature of the latter is a line of three stars, of which Altair, the middle one, is eleventh in the list of the brightest. Like most northern constellations the Eagle appears to us upside down; We may think of Altair as its heart, Theta its beak, Zeta and Epsilon-its tail, and Delta and lota its claws. In the east-north-east Pegasus is raising his head and mane. Epsilon is a brilliant sun which outshines ours more than 350 times.

In the east one of the Fishes has just risen. In the old drawings the Waterbearer is shown pouring a wide stream of water into this Fish's mouth. Beta Aquarii is another brilliant star a hundred thousand times brighter than our sun. Its immense distance reduces it to the third magnitude. Directly above Aquarius is Capricornus the Sea Goat; Its line- of stars is shaped like a Lucky Bone. Nestling beside the quadrilaterals of Sagittarius, the Southern Crown shines faintly almost in the zenith.

In the E.S.E. Beta Ceti has just risen. Above, it aro Sculptor and tho Southern Fish. Alpha Piscis Australia is a fine star, coming eighteenth in

the list of brightest stars. But it is one of tho nearest stars ana in absolute brightness only exceeds our sun about twenty-five times. Its oia name is Fomalhaut, meaning "the fish's mouth." A. little higher in the sky is the beautiful curve of Grus the Crane. In the S.E. the faint gioup Fornax, the Chemical Furnace, is just appearing. Above it is Phoenix, the emblem of immortality. This magic bird was said to light its own funeral pile once every five or six thousand years, and rise again from its ashes. Above it are Toucan tho American Goose, with the glorious globular cluster 47 Toueaui, Indus the Indian, and Pavo tho Peacock.

Between the S.E. and S. we see part of tho great river Eriaanus and the whole of Dorado the Sworrtfish, Reticulum tho Rhomboidal Net, and Hydrus the Water Snake. Alpha Eridani, or Achernar, is the ninth brightest star; a sun about 400 times as bright as ours. Dorado contains the Great Magellan Cloua, one of the two nearest cosmic systems beyond our Galaxy. The other is the Smaller Magellan Cloud in Toucan.

Due south near the horizon is Pictor, with "no -stars brighter than the third magnitude. Extending from the S. to the S.W. is tho great Ship'Argo. Alpha Carinae, or Canopus, is both in appearance and reality a very brilliant object. Sirius alone looks brighter, and Sirius owes this distinction to being one of the nearest stars. Sirius, inaeea, is fiffy times as bright as our Sun, but Canopus is 2800 times brighter than Sirius. Argo is noticeable for

three crosses. Canopus is the foot of an immense one, whose top is Lambda and whose crossbar is Delta Gamma Zeta. The other two are much smaller and are marked by Epsilon, Delta, Kappa, lota, and Beta, TJpsilon, Theta, Omega respectively. They are roughly parallel to the Southern Cross.

In the S.W. Antlia, the Air Pump, is close to the horizon. The Southern Cross is half-way to the zenith, with the Pointers directly above it, pointing downwards. Above them are the Triangle, the Wolf, ana the Altar. At the foot of the Cross is the little constellation, Musca the' Fly or Bee.

In the W.S.W. we see the long tail of Hydra the Snake, with Crater the Cup and.Corvus tho Crow hanging from it. Delta Corvi is a visual double, more than 300 light years away, with a combined intensity of about 900 times that of our Sun. High in the sky are the great groups of the Centaur and the Wolf. The wonderful globular cluster; Omega Centauri, can bo seen with the naked eye. To find it, start from Beta, the Pointer nearer to tho Southern Cross, go rather more than one Cross length'parallel to the Cross, thus reaching Epsilon,. and then go on nearly another Cross length to Omega. Due west the greater part of Virgo has risen. Alpha Virginis, or Spica, is fifteenth amongst the brightest stars. It is 360 light years away, ana. so must be more than 6000 times as bright as the Sun. Above.it Libra the Balance, ana then the beautiful curves of Scorpio lead to the zenith. Antares is a double star, 125 light years away. It is seventeenth among tho brightest stars, but outshines the Sun 750 times. '

In the N.W. Bootes the Herdsman is setting. Alpha Bootis, or Arctnrus, is the sixth star in brightness. It is comparatively near about; 40 light years away, ana is a sun about 200 times as bright as ours. Half-way to the zenith the hand of Ophiuchus grasps the Serpent, -whose head, really raised on high^ appears to us to hang nearly vertically downwards.

A little more towards the north, the Northern Crown is hear the horizon. Alpha is 360 times as bright as the Sun.

In the N.N.W. Hercules fills the lower part of the sky with Ophiuchus and Serpcns above it. Hercules, as we have seen, appears right way up. but to us Ophiuchus is inverted.