A Galaxy is not a Comet

Explanation: This gorgeous galaxy and comet portrait was recorded on April 5th in the skies over the Oriental Pyrenees near Figueres, Spain . From a site above 1,100 meters, astrophotographer Juan Carlos Casado used a guided time exposure, fast film, and a telephoto lens to capture the predicted conjunction of the bright Comet Ikeya-Zhang (right) and the Andromeda Galaxy (left). This stunning celestial scene would also have been a rewarding one for the influential 18th century comet hunter Charles Messier . While Messier scanned French skies for comets, he carefully cataloged positions of things which were fuzzy and comet-like in appearance but did not move against the background stars and so were definitely not comets. The Andromeda Galaxy , also known as M31, is the 31st object in his famous not-a-comet catalog . Not-a-comet object number 110 , a late addition to Messier's catalog, is one of Andromeda's small satellite galaxies, and can be seen here just below M31. Our modern understanding holds that the Andromeda galaxy is a large spiral galaxy some 2 million light-years distant . The photogenic Comet Ikeya-Zhang , now a lovely sight in early morning skies , is about 80 million kilometers (4 light-minutes) from planet Earth.