NGC 206
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NGC 206 is a bright star cloud in the Andromeda Galaxy, and the brightest star cloud in Andromeda when viewed from Earth. It was discovered by German-born English astronomer William Herschel in 1786<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and possibly even two years earlier when he observed "a streak of milky nebulosity, horizontal, or part of the 31st Nebula."
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NGC 206 is the richest and most conspicuous star cloud in the Andromeda Galaxy, and is one of the largest and brightest star-forming regions in the Local Group.<ref name=Massey1995> Template:Cite journal</ref> It contains more than 300 stars brighter than Mb=−3.6.<ref>Template:Cite book</ref> It was originally identified by Edwin Hubble as a star cluster but today, due to its size, it is classified as an OB association.<ref>Template:Cite book</ref>
NGC 206 is located in a spiral arm of the Andromeda Galaxy, in a zone free of neutral hydrogen. It contains hundreds of stars of spectral types O and B. The star cloud has a double structure: one region has an age of around 10 million years and includes several H II regions in its border; the other region has an age of 40 to 50 million years and includes a number of cepheids. The two regions are separated by a band of interstellar dust.<ref name=Chernin1995> Template:Cite journal</ref>
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