Galaxy
Andromeda Galaxy (M31)
In Andromeda (And) • Magnitude 3.4 • 3.2 degrees
Open the free AstroPlanner with Andromeda Galaxy pre-selected, scored against your telescope, location, and the live cloud forecast.
The nearest large spiral galaxy to our own Milky Way, containing roughly one trillion stars and stretching 220,000 light-years across — the most distant object visible to the naked eye at 2.5 million light-years. It is heading toward us on a collision course, and in about 4.5 billion years the two galaxies will merge; because stars are so far apart, virtually no actual star collisions will occur.
Andromeda Galaxy at a glance
| Catalog IDs | M31, N 224 |
| Type | Galaxy |
| Constellation | Andromeda (And) |
| Right ascension | 00h 42m 43s |
| Declination | +41° 16' 12" |
| Apparent magnitude | 3.44 |
| Surface brightness | 13.5 mag/arcsec² |
| Angular size | 190.0 × 60.0 arcmin |
| Max altitude at 45°N | 86° |
| Best imaging months | Jun, Jul, Aug |
How to image Andromeda Galaxy
Andromeda Galaxy sits in the constellation Andromeda at right ascension 00h 42m 43s and declination +41° 16' 12". 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, Andromeda Galaxy needs the darkest skies you can find: surface brightness, not just apparent magnitude, drives whether it will lift out of the gradient.