Anyone who has ever flipped through a phone book to find the name of a physician has seen the symbol: two serpents wrapped around a vertical staff that appears topped by a round knob and is flanked by wings. It's known as the "caduceus" and since 1902, when the U.S. Army adopted it as the insignia of its Medical Corps, it has been the emblem of the American medical profession. Many medical associations use what some call the "correct" symbol of medicine: the staff of Asclepius, with one serpent encircling a staff. Either way, people have long associated the serpent with medicine.
So what does this have to do with stargazing? Well, the ancient constellation of Serpens, the serpent, has long been recognized as a symbol of healing, and appears in our early evening sky this week. Not long after dark during June, we can find this figure midway up in the southeastern sky, held by the serpent-bearer Ophiuchus. Ophiuchus is believed to represent Aesculapiu, the ancient god of health and healing. Its brightest star is Rasalhague, Arabic for "Head of the Snake Charmer." And Serpens -- the only two-part constellation with its head on one side (Serpens Caput) and its tail on the other (Serpens Cauda) -- is draped across the front of his body.
Ophiuchus lies along some of the thickest star clouds of the Milky Way. If you have a sky unpolluted by city lights you'll have no trouble finding the Milky Way passing through this constellation. And just below, you'll find the brilliant reddish-orange star Antares.