Sky and Telescope - July 2018 - 67
p A MOST EXTRAORDINARY OBJECT Messier 27, also known as the Dumbbell Nebula, the Hourglass Nebula, and more recently, the Apple
Core Nebula, was first discovered by Charles Messier in 1764 and subsequently observed by William Herschel, who bestowed upon it the
"dumbbell" moniker. In this glorious composite image obtained with Antu, one of ESO's four Very Large Telescope 8.2-meter units in Chile, the
structure of the nebula is clearly seen. The red color in the outer parts of the nebula traces hydrogen expelled during the first phase of mass
loss from the red giant, while the green represents oxygen ejected during a second phase. North is up in all images.
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