Editing Mount Wilson Observatory (section)

{{Short description|Astronomical observatory in Los Angeles County, California, US}}
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{{Infobox Observatory
|location=[[Mount Wilson (California)|Mount Wilson]], California, US
|telescope1_name = [[#60-inch telescope|60-inch telescope]]
|telescope1_type = {{convert|60|in|m|order=flip|adj=on|sp=us}} reflector
|telescope2_name = [[#100-inch Hooker telescope|Hooker telescope]]
|telescope2_type = {{convert|100|in|m|order=flip|adj=on|sp=us}} reflector
|telescope3_name = [[Infrared Spatial Interferometer]]
|telescope3_type = 3 × {{convert|65|in|m|order=flip|adj=on|sp=us}} reflectors
|telescope4_name = [[CHARA array]]
|telescope4_type = 6 × {{convert|40|in|m|0|order=flip|adj=on|sp=us}} reflectors
}}

The '''Mount Wilson Observatory''' ('''MWO''') is an [[Observatory#Astronomical observatories|astronomical observatory]] in [[Los Angeles County, California]], United States. The MWO is located on [[Mount Wilson (California)|Mount Wilson]], a {{convert|1740|m|ft|abbr=off|adj=on|sp=us|order=flip}} peak in the [[San Gabriel Mountains]] near [[Pasadena, California|Pasadena]], northeast of Los Angeles.

The observatory contains two historically important telescopes: the {{convert|100|in|m|adj=on}} [[#100-inch Hooker telescope|Hooker telescope]], which was the largest aperture telescope in the world from its completion in 1917 to 1949, and the [[#60-inch telescope|60-inch telescope]] which was the largest operational telescope in the world when it was completed in 1908. It also contains the [[Snow solar telescope]] completed in 1905, the {{Convert|60|ft|sp=us|adj=on}} solar tower completed in 1908, the {{Convert|150|ft|sp=us|adj=on}} solar tower completed in 1912, and the [[CHARA array]], built by [[Georgia State University]], which became fully operational in 2004 and was the largest optical interferometer in the world at its completion.

Due to the [[inversion (meteorology)|inversion layer]] that traps warm air and [[smog]] over Los Angeles, Mount Wilson has steadier air than any other location in North America, making it ideal for astronomy and in particular for [[interferometry]].<ref name="lat">{{cite news | url=http://www.latimes.com/news/local/la-me-then6-2008jul06,0,6407442.story | title=Mount Wilson Observatory an astronomical gem | work=[[Los Angeles Times]] | date=July 6, 2008 | first=Wendy | last=Hansen}}</ref> The increasing [[light pollution]] due to the growth of greater Los Angeles has limited the ability of the observatory to engage in deep space astronomy, but it remains a productive center, with the CHARA array continuing important stellar research.

The initial efforts to mount a telescope to Mount Wilson occurred in the 1880s by one of the founders of [[University of Southern California]], [[Edward Falles Spence]], but he died without finishing the funding effort.<ref>Harris Newmark, ''Sixty Years in Southern California'' (1916).</ref> The observatory was conceived and founded by [[George Ellery Hale]], who had previously built the 1 meter telescope at the [[Yerkes Observatory]], then the world's largest telescope. The Mount Wilson Solar Observatory was first funded by the [[Carnegie Institution of Washington]] in 1904, leasing the land from the owners of the Mount Wilson Hotel in 1904. Among the conditions of the lease was that it allow public access.<ref>[http://www.sgvtribune.com/search/ci_6674075?IADID=Search-www.sgvtribune.com-www.sgvtribune.com Window to other worlds - SGVTribune.com<!-- Bot generated title -->]</ref>