Ophiuchus, constellation at about 17 hours right ascension and on the celestial equator in declination. Its brightest star is Rasalhague (from the Arabic for “the head of the serpent collector”), with a magnitude of 2.1. This constellation contains Barnard’s Star, the second nearest star to Earth at a distance of six light-years and the star with the largest proper motion. Kepler’s Nova, one of the few supernovas known to have occurred in the Milky Way Galaxy, appeared in Ophiuchus in 1604. In Greek mythology this constellation represented Asclepius, the Greek god of medicine. He is depicted as holding a serpent (the constellation Serpens), a symbol of renewal.