- Four dogs are to be found among the constellations: Canis Major, Canis Minor, and the two hunting dogs of Canes Venatici, but Canis Major is undoubtedly the top dog. Indeed, Ptolemy in the Almagest called it simply Κύων (Kyon), the Dog. Canis Major is dominated by Sirius, popularly termed the Dog Star, the most brilliant star in the entire night sky; almost certainly the constellation originated with this star alone.