Globular cluster
M5 (M5)
In Serpens (Ser) • Magnitude 6.0 • 23 arcminutes
Open the free AstroPlanner with M5 pre-selected, scored against your telescope, location, and the live cloud forecast.
Often considered the most beautiful globular cluster in the northern sky, M5 contains over 100,000 stars spanning 165 light-years, and is around 13 billion years old. Despite this great age, it harbours surprisingly young-looking "blue straggler" stars, thought to be born from stellar collisions within its dense core.
M5 at a glance
| Catalog IDs | M5, N 5904 |
| Type | Globular cluster |
| Constellation | Serpens (Ser) |
| Right ascension | 15h 18m 36s |
| Declination | +02° 04' 48" |
| Apparent magnitude | 5.95 |
| Surface brightness | 11.8 mag/arcsec² |
| Angular size | 23.0 × 23.0 arcmin |
| Max altitude at 45°N | 47° |
| Best imaging months | Feb, Mar, Apr |
How to image M5
M5 sits in the constellation Serpens at right ascension 15h 18m 36s and declination +02° 04' 48". 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.