The constellation of Bootes, the herdsman. Bootes is a large spring and summer constellation for observers in the northern hemisphere. It lies between Ursa Major (to the north) and Virgo (to the south) and contains the fourth brightest star in the sky, Arcturus (lower right). Arcturus is a normal orange star. It is cooler than the sun, but four times heavier and 115 times brighter. In mythology, Bootes represents Arcas, the son of Callisto. Callisto was changed into a bear (Ursa Major) and Arcas came across her whilst hunting. Not recognising her, he was about to kill her when Zeus intervened, avoiding the tragedy by placing them both in the heavens. See "Observing the constellations", page 28.