Messier 110, also cataloged as NGC 205, is a satellite galaxy of the great Andromeda Galaxy and one of the most rewarding faint companions to capture in a wide-field frame. Shining at an apparent magnitude of 8.07 with an angular size of 3.3′ × 2.1′, it presents as a soft, elongated glow with a relatively low surface brightness of about 18.8 mag/arcsec², which rewards dark skies and generous integration time. Because its diffuse light spreads across the frame, careful stretching and gradient control are essential to bring out the smooth halo without clipping the delicate outer regions. For most astrophotographers, Messier 110 is a natural bonus target framed alongside its dominant neighbor, adding depth and context to any Andromeda field.
Names and Catalog numbers
- M 110 (Messier 110)
- NGC 205
- UGC 426
- PGC 2429
Position and the cosmic neighborhood
Messier 110 sits in the constellation Andromeda at a right ascension of 00h 40m 22s and a declination of +41° 41′ 08″, placing it just off the sprawling disk of the Andromeda Galaxy. This proximity makes it one of the easiest satellite galaxies to include in the same composition, and imagers routinely capture it together with the brighter companion Messier 32 on the opposite side of the great spiral. Its high northern declination keeps it well placed for observers across the northern hemisphere, riding high in autumn skies. The rich field surrounding it, dense with faint stars and the outer glow of its parent galaxy, offers a satisfying sense of cosmic scale within a single frame.
Nice to Know
- Messier 110 (NGC 205) is a dwarf elliptical satellite of the Andromeda Galaxy, making it a perfect companion target in wide-field Andromeda captures.
- Its low surface brightness of about 18.8 mag/arcsec² means the smooth glow demands dark skies and long exposures to reveal its full extent.
- Despite its modest physical diameter of roughly 13,000 light-years, it presents a compact 3.3′ × 2.1′ profile that fits neatly within larger galaxy fields.
- With a radial velocity of about -246 km/s, Messier 110 is approaching us, a signature it shares with the broader Andromeda system that is moving toward the Milky Way.
Brightness, distance and size
The object has an apparent magnitude of 8.1 mag, it lies about 13.4 million light-years from Earth and spans roughly 13,000 light-years across. On the sky it appears about 3.3′ × 2.1′ in size.
