M27: Not a Comet . ... Credit Copyright: Martin Pugh Explanation: While hunting for comets in the skies above 18th century France, astronomer Charles Messier diligently kept a list of the things he encountered that were definitely not comets. ... Known by the popular name of the Dumbbell Nebula , the beautifully symmetric interstellar gas cloud is over 2.5 light-years across and about 1,200 light-years away in the constellation Vulpecula . ... NASA Web Site Statements, Warnings, and Disclaimers . ...