You guessed it - the one on the right is a globular star cluster. The diffuse greenish coma of periodic comet 10P/Tempel 2 is at left in the frame. In fact the globular star cluster is Messier 30, also known as M30, or the 30th entry in astronomer Charles Messier's catalog of things which are not comets. Recorded on July 29, this modern telescopic image captures periodic comet Tempel 2 as it briefly swept close on the sky to M30. While the periodic comet's faint, narrow, orbital dust trail seems to pierce the globular star cluster, Tempel 2 was a mere 3.5 light-minutes away.