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M21 (NGC 6531)

Typ:Open cluster
Constellation:Sagittarius
Size:13'
Distance:4.25 kLj
Brightness:6.5 mag
Position:RA:18h 04.6m DEC:−22° 30′
Max. height:17.50°, Jun. (midnight at +50°N)
Show in Stellarium
Discovered:Charles Messier, 1764
Details:Read more on Wikipedia

Compared to its prominent neighbor M20, the Trifid Nebula, M21 is a somewhat plain open cluster. It is too dark to be visible by the naked eye and requires at least binoculars and a dark sky for visual observation.

The next image shows the full frame with the Trifid Nebular M20 in the center and a part of the Lagoon Nebula M8 on the right after a manual edit (580mm, ASI2600MM, LRGB 1h).