Every year during May, the fabled Southern Cross and the star closest to our Earth other than the Sun are visible for a brief time after sunset.

One hour after sunset in the southern parts of the northern hemisphere, face south and see four stars. Draw lines between them to make the Crux Australis, the Southern Cross.

To its left and close to the horizon you’ll see two bright stars, Beta Centauri and Alpha Centauri. To see them really well, wait until the Southern Cross sets and Beta and Alpha Centauri replace it due south.

The star closest to the Cross is Beta Centauri, a blue-white double star, each about eight times the size of our Sun.

Its companion, Alpha Centauri, is the real winner. In addition to being the fourth brightest star we can see with the naked eye, it is also the closest star to Earth other than our Sun. Still, that’s very far away. Our Sun is 93 million miles away; Alpha Centauri is 26 trillion miles away.

Or think of it this way: It takes 8 1/3 minutes for light to reach us from the Sun but it takes 4 1/3 years for light to reach us from Alpha Centauri, which is actually three stars that look like one because they are so far away.

Back to the Cross. If you look closely you will see that in addition to its four stars there is a fifth, not-quite-so-bright star just off center, which bothered American author Mark Twain so much that he threatened to write his congressman and urge that it be moved to the center.

The last weekend in May will be perfect for star gazing because of a new Moon, which means no Moon glow so stars will really stand out.

At about an hour after sunset, face north and you will see the seven stars of the Big Dipper. Every spring, the Dipper reaches its highest positions above the North Star. In early spring it is to its right (east), and in late spring it is to its left (west).

Once you find the Big Dipper, draw a line through the three handle stars, extend that arc and land on the third brightest star in the heavens, Arcturus, which is 26 times as wide as our Sun.

Next, continue that arc and you’ll speed right on to Spica, the brightest star of Virgo, the virgin. Although it is only a third the size of Arcturus, it is still eight times the size of our Sun.

Jack Horkheimer is executive director of the Miami Museum of Science. This is the script for his weekly television show co-produced by the museum and WPBT Channel 2 in Miami. It is seen on public television stations around the world. For more information about stars, visit www.jackstargazer.com .