Open cluster
Jewel Box Cluster (NGC4755)
In Crux (Cru) • Magnitude 99.0 • 7.8 arcminutes
Open the free AstroPlanner with Jewel Box Cluster pre-selected, scored against your telescope, location, and the live cloud forecast.
Iconic open cluster in Crux with contrasting blue and red supergiants.
Jewel Box Cluster at a glance
| Catalog IDs | N 4755 |
| Type | Open cluster |
| Constellation | Crux (Cru) |
| Right ascension | 12h 53m 37s |
| Declination | -60° 21' 23" |
| Apparent magnitude | 99.00 |
| Angular size | 7.8 × 7.8 arcmin |
| Max altitude at 45°N | Below horizon |
| Best imaging months | Mar, Apr, May |
How to image Jewel Box Cluster
Jewel Box Cluster sits in the constellation Crux at right ascension 12h 53m 37s and declination -60° 21' 23". 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.