Gary Imm

GaryI

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A backyard amateur astrophotographer enjoying retirement with my wife on beautiful Lake Livingston in Onalaska, Texas, about 90 minutes north of Houston.

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All planetary nebulae come from the same process - the death of a medium sized star. The smallest of the deep sky objects, a planetary nebula is a glowing gas shell, generally circular, formed when ionized gas is expelled into the surrounding interstellar space. The expelling of this gas signals that the star is passing through the last stage in its life, on its way to collapsing into a dense white dwarf. As the star collapses, the outer gas layers become energized and illuminated by ultraviolet radiation from the dwarf at their center. Over 200 years ago, these objects were termed "planetary nebulae" by William Herschel because of their planet-like appearance through 18th century telescopes. But since a nebula has nothing to do with a planet, this label has led to confusion ever since. The PN below are listed in the order of their designation.