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Messier 23 |
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 | The irregular star cluster M23, or NGC6494, is a bright, large, rich, rather attractive, cluster in the constellation Sagittarius. Some 2200 light-years away, M23 has a diameter of about 20 light-years (around 30 minutes of arc): this picture is 35 minutes across. M23 is over 200 million years old. As M23 is in the galactic plane, the background stars are increasingly reddened by dust absorption, and this image has several black areas where any distant stars are hidden by the thick dust. The bright star to the NW (upper right) is a foreground object. This is a large open cluster. In a 8-inch at 49X, it is framed nicely within the field of view. The most interesting aspect of this cluster is that it consists of several little chains of stars going in all directions. Easily 50-60 stars are visible of varying magnitudes, including a lot of bright ones. Some of the chains are straight and some form nice little arcs, giving the cluster an interesting texture. |
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M23 NGC 6494 Other description: Open cluster dense. Constellation: Sagittarius Dreyer description: Cluster, bright, very large, westward rich in stars, little compressed, stars of magnitude 10 and fainter; = M23. Magnitude: 5.5 RA: 17h 57m 03.7s Dec: -19°01'09" RA: 17h 56m 48.0s Dec: -19°01'00" (Epoch 2000) Azm: 176°26'24" Alt: +24°37'34" Rise: 20:06 Transit: 00:44 Set: 05:26 Size:27.0' |