Dumbbell Nebula Halo . ... Credit Copyright: Robert Gendler Explanation: In 1764, French astronomer Charles Messier sighted this gorgeous cosmic cloud which he described as an oval nebula without stars. ... The picture is a composite that includes 8 hours of exposure through a filter designed to record only the light of hydrogen atoms, tracing the intricate details of the nebula's faint outer halo which spans light-years. ... NASA Web Site Statements, Warnings, and Disclaimers . ...