Since autumn, the sky has appeared to make a quarter turn as a consequence of Earth’s revolution around the Sun. Crux and the Southern Pointers, the stars Rigil Kent and Hadar, have now migrated to the west but still remain well above the southwestern horizon. Antares in the constellation Scorpius lies just west of the zenith.
The bright star Achernar (“ACK-er-nar”) now rises in the southeast. This star marks the end of the long and otherwise dim constellation Eridanus, the River. High in the east, look for the star Fomalhaut (“FOAM-a-lot”), the brightest star in Piscis Austrinus, the Southern Fishes. The misty patches of the Magellanic Clouds lie over the south-southeastern horizon.
Low in the northern sky, look for the dazzling blue-white star Vega in the small parallelogram-shaped constellation Lyra. And slightly lower still, the star Deneb shines in the constellation Cygnus, the Swan. Cygnus is a large cross-shaped constellation, so these stars are sometimes called the “Northern Cross”. Further towards the zenith, well above the northern horizon, look for the white light of the star Altair in the constellation Aquila, the Eagle. The three bright stars Altair, Vega, and Deneb form what is sometimes called the “Northern Triangle”.
Perhaps the finest celestial sight of the southern winter sky is the long arc of the star clouds of the Milky Way running from north to south. There are millions of unresolved stars in the clouds, along with foreground clumps of dark gas and dust that obscure the light from more distant stars. The stars are thickest directly overhead, in the constellation Scorpius and the “teapot”-shaped constellation Sagittarius. Towards the tip of the teapot of Sagittarius lies the center of our galaxy, which is why the star clouds of the Milky Way appear so thick in this part of the sky. In the northern hemisphere, this region lies low on the southern horizon, but in the south the full grandeur of the richest part of the Milky Way is right overhead.
The constellations Sagittarius and Scorpius and the thick star clouds of the Milky Way are nearly directly overhead in the evening hours in in mid-August
The star clouds of the Milky Way are very difficult to see from urban areas where bright city lights wash them out, but they are very obvious in clear sky far away from city lights. If you have dark sky, look for small, misty, unresolved patches in Sagittarius and Scorpius. These are yet more groups of distant star clusters and nebulae where new stars are in the process of forming. They are dazzling sights in binoculars or a small telescope.