One of the dog’s names is assigned to the, astronomically speaking, nearby large star Sirius in the constellation Canis Major (“Big Dipper”). Sirius is the brightest star in the sky. The other dog’s name is assigned to Procyon, located in the constellation Canis Minor (“Little Dipper”). Mythology has it that Diana put Orion and these two dogs in the sky.
From liveinternet.ru/community/lj_costume_history/.