Lot of 8 Keystone View Company astronomy stereoview cards, numbers 593-600, photographed at Yerkes Observatory: 593 The Sun; 594 The Full Moon; 595 Moon at Age of Seventeen Days; 596 The Planet Mars; 597 The Planet Saturn; 598 The Planet Uranus and Two of its Moons; 599 Meteor in Constellation of Orion; 600 Morehouse's Comet. Each card has its description printed on the back. Each card measures about 7 x 3-1/2 in. Sold as one lot.