Among the constellations of the southern heavens near the meridian in February we see in addition to Argo Navis the constellations of Dorado, The Goldfish; Hydrus, The Serpent, and Tucana, The Toucan. Though insignificant in appearance Dorado contains what was described by Sir John Herschel as one of the most extraordinary objects in the heavens, a worthy rival of The Great Orion Nebula and in some respects very similar to it, The Great Looped Nebula, "the center of a great spiral." In Dorado also is located The Greater Magellanic Cloud which looks like a detached portion of the Milky Way though it is far removed from it. To the naked eye it resembles a small white cloud about 4° in extent. In the telescope it bears a close resemblance to a typical portion of the Milky Way. A similar formation known as The Lesser Magellanic Cloud is located in Hydrus. It has been estimated that the distance of The Lesser Cloud is 80,000 light-years and that it is receding from us.
In Tucana is located one of the finest globular star clusters in the heavens, known as 47 Tucanæ. This cluster and Omega Centauri, a globular star cluster in Centaurus, are the two nearest of all the globular clusters. They are distant from the earth about 22,000 light-years and it is known that the combined light of the thousands of stars of which each cluster is composed is about one million times that of our own sun.
In the western sky in the southern hemisphere in February may be seen the brilliant, white, first-magnitude star Achernar in the river Eridanus, the long, winding constellation that, we recall, starts near the brilliant Rigel in Orion and disappears from the view of northern observers below the southern horizon, extending its course far into the southern hemisphere. Achernar means "The End of the River" and this is nearly its position in the constellation.
Though Argo Navis is the largest and most important constellation of the southern hemisphere, Crux, The Southern Cross, far-famed in story and legend as well as for its historical associations, is beyond a doubt the most popular.
The best time to view the Southern Cross is in June or July when it is near the meridian. It is not seen to advantage in the months of January or February. It then lies on its side and close to the horizon and therefore is dimmed by atmospheric haze so that it almost invariably is a disappointing object to the tourist from the north who usually views it for the first time in one of these months. The Cross is viewed to advantage in the latitude of Rio or Valparaiso and it is best seen from the Straits where it rides high overhead. It is not seen to advantage from the latitudes of Cuba or Jamaica. It is small, only 6° in extent from north to south and less in width and it lies in the most brilliant portion of the Milky Way which is here a narrow stream only three or four degrees wide. Directly below the Cross is the noted Coal Sack, apparently a yawning chasm in the midst of its brilliant surroundings though probably in reality a dark nebula. Viewed with the telescopes a number of stars are to be seen projected on this dark background.
The Southern Cross is to the inhabitants of the southern hemisphere what the Big Dipper is to those who dwell in the northern hemisphere—an infallible timepiece. The upright of the Cross points toward the south pole of the heavens which lies in a region where there is a singular dearth of bright stars, the nearest star to the south pole being a faint fifth-magnitude star called Sigma Octantis. When seen in the southeast or southwest the Cross lies on its side, but when passing the meridian it stands nearly upright. Humboldt, referring to this fact, says:
"How often have we heard our guides exclaim in the savannahs of Venezuela and in the desert extending from Lima to Truxillo, 'Midnight is past, the Cross begins to bend.'"
By the explorers of the sixteenth century the Cross was taken as a sign of heaven's approval of their attempt to establish the Christian religion in the wilds of the New World. This thought is beautifully expressed in Mrs. Hemans' lines in "The Cross of the South."
"But to thee, as thy lode-stars resplendently burn
In their clear depths of blue, with devotion I turn
Bright Cross of the South! and beholding thee shine,
Scarce regret the loved land of the olive and vine.
Thou recallest the ages when first o'er the main
My fathers unfolded the ensign of Spain,
And planted their faith in the regions that see
Its imperishing symbol ever blazoned in thee."
Alpha Crucis, the brightest star in Crux, is at the foot of the Cross. It consists in reality of two second-magnitude stars forming a beautiful double while a third fifth-magnitude star one and one-half minutes of arc distant makes with this pair a combination similar to our Mizar and Alcor of the Big Dipper though the separation is not great enough to be visible to the naked eye. The second-magnitude star at the head of the Cross is a deep orange in color and the two stars that mark the ends of the cross-arm are white third-magnitude stars.