Autumn Night Sky (Southern Hemisphere)

In the early autumn sky of the southern hemisphere, a dazzling band of bright stars runs from the southeast to the west.  Look directly at the western end of this band in the mid-evening hours to see the blue-white star Sirius, the brightest star in the night sky.  Turn a little to the southwest to see the bright white star Canopus, the second-brightest star in the sky.  Both stars are much higher during the summer months, and you will visit their home constellations of Canis Major and Carina during that season.

The sky at 9 p.m. on May 15 from 35 degrees S latitude. Click to open in a new window.

The sky at 9 p.m. on May 15 from 35 degrees S latitude. Click to open in a new window.

Overhead, just a little south of the zenith, look for a small group of bright stars.  Four of these stars form the distinctive shape of the Southern Cross, a group that’s part of the small constellation Crux.  The image below shows the shape of this small constellation.  It’s a small group, just about 5 degrees from tip to tip… that’s about as large as your middle three fingers held together at arm’s length.  The star at the “top” of the cross is called Gacrux, the star at the bottom is Acrux.  The star at the eastern tip of the cross is called Mimosa.

Just to the east of Crux, look for two more bright stars.  The slightly fainter blue-white star is Hadar.  The brighter yellow star is called Rigel Kent, and it is also known as Alpha Centauri because it is the brightest star in the constellation Centaurus.  It’s also the closest bright star to Earth and the third-brightest star in the night sky after Sirius and Canopus.

Crux and the “Southern Pointers” show the direction to the SCP

Crux and the stars Hadar and Rigil Kent also point the way to the south celestial pole.  These two stars are sometimes called the “Southern Pointers”.  Follow a line south from Crux, and another line south from the mid-point between Hadar and Rigil Kent.  These imaginary lines cross just 5 degrees northwest of the south celestial pole (SCP). 

Crux and the “Southern Pointers” show the direction to the SCP

Crux and the “Southern Pointers” show the direction to the SCP

Look just west of Crux along the thick band of stars to see the large irregular outline of the constellation Vela.  South of Vela lies Carina, another sprawling constellation of which Canopus is the brightest star.  If you look at these constellations under dark sky, you will notice many faint misty patches.  These are small clusters of new stars as well as glowing clouds of gas in which new stars are forming.  Many of these patches are quite stunning in a telescope or pair of binoculars.

South of the starry band that includes Crux and the Pointers lie the Magellanic Clouds.  These are small unresolved “dwarf” galaxies of a few million stars well outside of our own Milky Way galaxy. They are visible only from the deep southern hemisphere.

The sky towards the north contains only three bright stars: Arcturus, Spica, and Regulus in the constellations Bootes, Virgo, and Leo, respectively.  In this direction, you are looking out of the starry plane of the Milky Way, which is why you see few bright foregrounds stars in this part of the sky.  But a telescope will reveal hundreds of distant galaxies in this region of the sky, especially the galaxies of the Virgo galaxy cluster, which lies just southeast of the star Denebola in Leo.  The star Arcturus, just over the northern horizon, is the 4th brightest star in the night sky.  So at this time of year you can see the four brightest stars in the night sky.

Look now to the southeast.  Here you will find the striking sight of the rising constellation Scorpius, its claws pointing northeast and its menacing stinger, rich with clouds of stars and star clusters, hanging in the southeast.  The bright red-orange star at the “heart” of the Scorpion is called Antares.