Globular cluster
M9 (M9)
In Ophiuchus (Oph) • Magnitude 8.4 • 12 arcminutes
Open the free AstroPlanner with M9 pre-selected, scored against your telescope, location, and the live cloud forecast.
A compact globular cluster nestled near the heart of the Milky Way, partially veiled by intervening dust clouds. Without that dust it would appear about 3 magnitudes brighter — the equivalent of looking at a flashlight through dark smoke.
M9 at a glance
| Catalog IDs | M9, N 6333 |
| Type | Globular cluster |
| Constellation | Ophiuchus (Oph) |
| Right ascension | 17h 19m 12s |
| Declination | -18° 31' 12" |
| Apparent magnitude | 8.42 |
| Surface brightness | 12.8 mag/arcsec² |
| Angular size | 12.0 × 12.0 arcmin |
| Max altitude at 45°N | 26° |
| Best imaging months | Mar, Apr, May |
How to image M9
M9 sits in the constellation Ophiuchus at right ascension 17h 19m 12s and declination -18° 31' 12". 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.