Open star cluster M23
Open star cluster M23 is in the constellation Sagittarius (Sgr).
Equatorial coordinates (epoch J2000):
Ra 17h56.8m, Dec -19° 01'
Visual magnitude: 6,0m
Distance from the star clusters M23 to the Sun is 2050 light years
Angular size: 35'
External dimensions the star clusters M23 are about 20 light years.
Number of stars: 177
Age of the object M23 is 300x106 years
Discoverer: Charles Messier, 1764 year.
The designation M23 in other catalogs: NGC 6494
Optimum magnification for a telescope with observations of M23, depending on the aperture of the telescope (D), is about 10x-25x. Higher magnifications of course add details, but lead to a strong drop in the brightness of the image, making it difficult to observe.
The best month for observing M23 is July.
For observers in the northern latitudes:The nights in July are still quite light, so it makes sense to try to observe M23 also in August.
The first half of August is also not very dark, in addition the object will be at midnight not at its highest point,which provides the least exposure and atmospheric distortion. But, the difference is not so noticeable.And already in the second half of August the night sky becomes quite dark for observations (although in September it will more darker).The farther south the place of your observation is located, the earlier the sky will darken - both in time on the clock and on the calendar.
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