AND, ASTRONOMER, ASTRONOMICAL, ASTRONOMY, AT, BABACK, CELESTIAL, COMET, COMETS, DAVID, DISCOVERED, DISCOVERER, HE, HIS, HOME, LEVY, MOST, NEAR, OBSERVATION, OBSERVATORY, OF, POPULARIZER, PORTRAIT, SCIENCE, SCIENTIST, TAFRESHI, TELESCOPE, THE, TUCSON, WHERE, WORLD-KNOWN,