Astronomy Picture of the Day . ... Clearly visible for the first time were long light-colored cirrus-type clouds floating high in Neptune's atmosphere. ... During the Astro-1 astronomy mission of December, 1990, Space Shuttle astronauts photographed this stunning view of the setting full moon poised above the Earth's limb. ... Asteroid 1998 KY26 . ... X Ray Moon . ... This x-ray image of the Moon was made by the orbiting ROSAT (R ntgensatellit) Observatory in 1990. ... Aristarchus Plateau . ...