Open cluster
M34 (M34)
In Perseus (Per) • Magnitude 5.2 • 35 arcminutes
Open the free AstroPlanner with M34 pre-selected, scored against your telescope, location, and the live cloud forecast.
A young, scattered open cluster in Perseus at about 1,500 light-years — close enough that a wide-field telescope can resolve individual star colours, from hot blue-white giants to slightly cooler yellow stars. Its 100+ stars span an area about twice the diameter of the full Moon.
M34 at a glance
| Catalog IDs | M34, N 1039 |
| Type | Open cluster |
| Constellation | Perseus (Per) |
| Right ascension | 02h 42m 00s |
| Declination | +42° 46' 48" |
| Apparent magnitude | 5.20 |
| Angular size | 35.0 × 35.0 arcmin |
| Max altitude at 45°N | 88° |
| Best imaging months | Jul, Aug, Sep |
How to image M34
M34 sits in the constellation Perseus at right ascension 02h 42m 00s and declination +42° 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.