Galaxy
M109 (M109)
In Ursa Major (UMa) • Magnitude 10.6 • 7.5 arcminutes
Open the free AstroPlanner with M109 pre-selected, scored against your telescope, location, and the live cloud forecast.
A beautiful barred spiral galaxy in Ursa Major, one of the brightest in its region of sky. The bar at its centre spans tens of thousands of light-years end to end — a structure comparable in size to the distance between the Milky Way and its nearest satellite galaxies.
M109 at a glance
| Catalog IDs | M109, N 3992 |
| Type | Galaxy |
| Constellation | Ursa Major (UMa) |
| Right ascension | 11h 57m 36s |
| Declination | +53° 22' 12" |
| Apparent magnitude | 10.60 |
| Surface brightness | 13.8 mag/arcsec² |
| Angular size | 7.5 × 4.4 arcmin |
| Max altitude at 45°N | 82° |
| Best imaging months | Dec, Jan, Feb |
How to image M109
M109 sits in the constellation Ursa Major at right ascension 11h 57m 36s and declination +53° 22' 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, M109 needs the darkest skies you can find: surface brightness, not just apparent magnitude, drives whether it will lift out of the gradient.