Mars visits the Milky Way
September, 2001 Observer's Notebook

by John Rummel

These cool September evenings are perfect for stargazing. All month, Mars can be found in the constellation Sagittarius, buried amidst the wonder of the summer Milky Way. If you're viewing from light-polluted Madison skies, all you'll see will be brilliant orange Mars and the "teapot" shape of Sagittarius. To really enjoy this part of the sky, take your binoculars and the sky chart on this page and go find some dark country skies.

Scanning the sky just above Mars, you'll be impressed with the richness of this region -the heart of the Milky Way galaxy. Numerous star clusters and nebulae inhabit this wonderful area of the sky. In particular, you'll notice two fuzzy spots, both just above the "spout" of the teapot. These are known to astronomers as M20 and M8, or more popularly known as the Trifid and Lagoon nebulae. Both nebulae have star clusters embedded within them, and both are likely places where new star formation is happening. The Trifid is a bit closer to us - about 2,000 light years compared to nearly 6,000 for the Lagoon. Binoculars will reveal the faint milky white glow of nebula in each object. Small telescopes will reward the observer with much more detailed looks at each of these fascinating objects.

Scan below Mars and just beneath the spout and you'll notice a beautiful cluster of stars. This is known as M7 or Ptolemy's cluster, since it was first mentioned by that great Greek astronomer in about AD 130. Robert Burnham, in his classic Celestial Handbook, notes "M7 is a large and brilliant group, easily detected with the naked eye... the cluster is seen projected on a background of numerous faint and distant Milky Way stars."

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