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| | Phobos (moon) - Wikipedia, the free encyclopedia |
 | | Phobos was discovered by American astronomer Asaph Hall on August 18, 1877, at the US Naval Observatory in Washington, D.C., at about 09:14 GMT (contemporary sources, using the pre-1925 astronomical convention that began the day at noon, give the time of discovery as August 17 16:06 Washington mean time). |
 | | Phobos was photographed close-up by Mariner 9 in 1971, Viking 1 in 1977, Phobos 2 in 1988, Mars Global Surveyor in 1998 and 2003, and by Mars Express in 2004. |
 | | Phobos' phases, in as much as they could be observed from Mars, take 0.3191 days to run their course (Phobos' synodic period), a mere 13 seconds longer than Phobos' sidereal period. |
| en.wikipedia.org /wiki/Phobos_(moon) (1762 words) |
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