Combination of 15, 1 minute images.
SBIG ST-8XE CCD.
5" f/5 refractor at prime focus.
| Object Type | Open Cluster |
| Constellation | Sagittarius |
| Magnitude | 6.5 |
| 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.