|Object Type||Open Cluster|
|Size||13.0' x 13.0'|
M 21 is a fairly compact cluster of moderately bright stars in Sagittarius, located about 1 degree north of the emission nebula, M 20 (the Trifid Nebula), visible in the image below at the bottom right. M 21 is near the top of the image. M 21 is visible to the naked eye from a dark location.