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The Engraved Hourglass Nebula (also known as MyCn 18) is a young planetary nebula in the southern constellation Musca about 8,000 light-years from Earth. It was discovered by Annie Jump Cannon and Margaret W. Mayall during their work on an extended Henry Draper Catalogue (the catalogue was built between 1918 and 1924).
A planetary nebula, abbreviated as PN or plural PNe, is a kind of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. The word nebula is Latin for mist or cloud, and the term planetary nebula is a misnomer that originated in the 1780s with astronomer William Herschel because, when viewed through his telescope, these objects resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and