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| | Ursa Minor (Site not responding. Last check: 2007-10-13) |
 | | The constellation of Ursa Minor, though not very brilliant, is important since it contains the North Pole, indicated by Polaris, the principal star of the constellation. |
 | | Polaris is a yellow supergiant which is about 600 light-years away: it is not exactly at the North Pole, but it is at a distance of less than one degree; because of the precession, however, it is approaching the Pole (it will return to get further after 2100). |
 | | Polaris is a variable star, which oscillates between magnitude 2,1 and 2,2 with a period of about 4 days, and besides it is a double star, considering that it has a companion of ninth magnitude. |
| www.astrofilitrentini.it /mat/costell/umi_e.html (139 words) |
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