Open cluster
Owl Cluster (NGC457)
In Cassiopeia (Cas) • Magnitude 6.4 • 7.8 arcminutes
Open the free AstroPlanner with Owl Cluster pre-selected, scored against your telescope, location, and the live cloud forecast.
A bright open cluster in Cassiopeia, also called the ET Cluster.
Owl Cluster at a glance
| Catalog IDs | N 457 |
| Type | Open cluster |
| Constellation | Cassiopeia (Cas) |
| Right ascension | 01h 19m 33s |
| Declination | +58° 17' 27" |
| Apparent magnitude | 6.40 |
| Angular size | 7.8 × 7.8 arcmin |
| Max altitude at 45°N | 77° |
| Best imaging months | Sep, Oct, Nov, Dec, Jan |
How to image Owl Cluster
Owl Cluster sits in the constellation Cassiopeia at right ascension 01h 19m 33s and declination +58° 17' 27". 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.