NGC 869
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The Double Cluster, NGC 869 (right) and |
|
| Observation data: J2000 epoch | |
|---|---|
| Class: | - |
| Constellation: | Perseus |
| Right ascension: | 02h 19.1m[1] |
| Declination: | +57° 09′[1] |
| Distance: | 6.8 kly[2] (2.1 kpc[2]) |
| Apparent magnitude (V): | 5.3[1] |
| Apparent dimensions (V): | 30′[citation needed] |
| Physical characteristics | |
| Mass: | (- M☉) |
| Radius: | - |
| VHB: | - |
| Estimated age: | 19 My[citation needed] |
| Notable features: | - |
| Other designations: | Collinder 24,[1] Melotte 13,[1] |
| See also: Open cluster, List of open clusters | |
NGC 869 is an open cluster located 6800 light years[2] away in the constellation of Perseus. The cluster is most likely around 19[2] million years old. It is the easternmost of the Double Cluster with NGC 884. Located in the Perseus OB1 association both clusters are located physically close to one another, only a few hundred light years apart. The clusters were first recorded by Hipparchus, but have likely been known since antiquity.
The Double Cluster is a favorite of amateur astronomers. These bright clusters are often photographed or observed with small telescopes. Easy to find, the clusters are visible with the unaided eye between the constellations of Perseus and Cassiopeia as a brighter patch in the winter Milky Way.
In small telescopes the cluster appears as a beautiful assemblage of bright stars located in a rich star field. Dominated by bright blue stars the cluster also hosts a few orange stars that add to the visual interest.
Sometimes known as h Per this designation more probably refers to a nearby dim star[3].
[edit] External links
[edit] References
- ^ a b c d e f g SIMBAD Astronomical Database. Results for NGC 869. Retrieved on December 22, 2006.
- ^ a b c d N.V. Kharchenko, A.E. Piskunov, S. Röser, E. Schilbach, and R.-D. Scholz, 2005, "Astrophysical Parameters of Galactic Open Clusters", Astronomy and Astrophysics, Volume 438, Issue 3, August 2005, pp.1163-1173
- ^ Stephen James O'Meara and Daniel W.E. Green, 2003, "The Mystery of the Double Cluster", Sky and Telescope,Vol. 105, No. 2, p. 116-119 (February 2003)
