Galaxy
Whirlpool Galaxy (M51)
In Canes Venatici (CVn) • Magnitude 8.4 • 11 arcminutes
Open the free AstroPlanner with Whirlpool Galaxy pre-selected, scored against your telescope, location, and the live cloud forecast.
One of the first objects ever identified as a spiral nebula, its structure recognised in 1845 using a 72-inch telescope. The Whirlpool is currently gravitationally devouring its smaller companion galaxy NGC 5195, and that interaction is triggering intense star formation — the collision is a cosmic factory producing new stars at a furious rate.
Whirlpool Galaxy at a glance
| Catalog IDs | M51, N 5194 |
| Type | Galaxy |
| Constellation | Canes Venatici (CVn) |
| Right ascension | 13h 29m 53s |
| Declination | +47° 11' 24" |
| Apparent magnitude | 8.36 |
| Surface brightness | 13.0 mag/arcsec² |
| Angular size | 11.0 × 7.0 arcmin |
| Max altitude at 45°N | 88° |
| Best imaging months | Jan, Feb, Mar |
How to image Whirlpool Galaxy
Whirlpool Galaxy sits in the constellation Canes Venatici at right ascension 13h 29m 53s and declination +47° 11' 24". 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, Whirlpool Galaxy needs the darkest skies you can find: surface brightness, not just apparent magnitude, drives whether it will lift out of the gradient.