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| | Messier Object 25 |
 | | Eventually, M25 was added to the second Index Catalog by J.L.E. Dreyer in 1908, based on photographic observations and using a position obtained by Solon Irving Bailey (1854-1931), published in Bailey (1908). |
 | | The occurance of the Delta Cephei star is consistent with the fact that it is not a very young cluster, its age may be about 90 million years (the Sky Catalog 2000 gives 89 million). |
 | | Also, as the distance of M25 is quite wellknown by other means, U Cephei can by used as one gauging point of the famous, so-called Cepheid distance scale, which is used for distance determinations of nearby galaxies. |
| www.seds.org /messier/m/m025.html (420 words) |
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