Galaxy
Cetus A (M77)
In Cetus (Cet) • Magnitude 9.6 • 7.0 arcminutes
Open the free AstroPlanner with Cetus A pre-selected, scored against your telescope, location, and the live cloud forecast.
One of the closest Seyfert galaxies — a type with an unusually luminous, actively feeding nucleus powered by a supermassive black hole of about 15 million solar masses. This actively accreting black hole makes M77's core alone brighter than billions of ordinary stars.
Cetus A at a glance
| Catalog IDs | M77, N 1068 |
| Type | Galaxy |
| Constellation | Cetus (Cet) |
| Right ascension | 02h 42m 43s |
| Declination | -00° 00' 36" |
| Apparent magnitude | 9.60 |
| Surface brightness | 13.3 mag/arcsec² |
| Angular size | 7.0 × 6.0 arcmin |
| Max altitude at 45°N | 45° |
| Best imaging months | Jul, Aug, Sep |
How to image Cetus A
Cetus A sits in the constellation Cetus at right ascension 02h 42m 43s and declination -00° 00' 36". 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. As a galaxy, Cetus A needs the darkest skies you can find: surface brightness, not just apparent magnitude, drives whether it will lift out of the gradient.