Globular cluster
M12 (M12)
In Ophiuchus (Oph) • Magnitude 7.7 • 16 arcminutes
Open the free AstroPlanner with M12 pre-selected, scored against your telescope, location, and the live cloud forecast.
A loosely concentrated globular cluster in Ophiuchus that appears more open and spread out than most. Astronomers found it has unusually few low-mass stars — the Milky Way's gravity has been slowly stealing them away over billions of years, acting like a cosmic pickpocket.
M12 at a glance
| Catalog IDs | M12, N 6218 |
| Type | Globular cluster |
| Constellation | Ophiuchus (Oph) |
| Right ascension | 16h 47m 13s |
| Declination | -01° 57' 00" |
| Apparent magnitude | 7.68 |
| Surface brightness | 12.1 mag/arcsec² |
| Angular size | 16.0 × 16.0 arcmin |
| Max altitude at 45°N | 43° |
| Best imaging months | Feb, Mar, Apr |
How to image M12
M12 sits in the constellation Ophiuchus at right ascension 16h 47m 13s and declination -01° 57' 00". To frame and integrate it well, AstroPlanner will compute the optimal moonless window for tonight from your location, the field-of-view fit against your sensor and focal length, the suggested total integration time given your aperture and sky Bortle class, and a cloud-aware schedule that drops it from the plan if your nearest cloud forecast spike overlaps the best altitude window.