Globular cluster
M71 (M71)
In Sagitta (Sge) • Magnitude 8.5 • 7.2 arcminutes
Open the free AstroPlanner with M71 pre-selected, scored against your telescope, location, and the live cloud forecast.
A globular cluster whose identity was debated by astronomers for over a century — it was unclear whether it was a very loose globular or an unusually concentrated open cluster. It wasn't conclusively classified as a genuine globular until the 1970s, when detailed measurements of its stars' ages finally settled the question.
M71 at a glance
| Catalog IDs | M71, N 6838 |
| Type | Globular cluster |
| Constellation | Sagitta (Sge) |
| Right ascension | 19h 53m 49s |
| Declination | +18° 46' 48" |
| Apparent magnitude | 8.50 |
| Surface brightness | 12.4 mag/arcsec² |
| Angular size | 7.2 × 7.2 arcmin |
| Max altitude at 45°N | 64° |
| Best imaging months | Apr, May, Jun |
How to image M71
M71 sits in the constellation Sagitta at right ascension 19h 53m 49s and declination +18° 46' 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.