M110 (Galaxy)
A dwarf elliptical galaxy 0.6° from the core of the Andromeda Galaxy, one of its satellites. It was the last object added to the Messier list, long after Messier died.
Galaxy in Andromeda. Magnitude 8.2.
Can you see it from Guyana?
From Georgetown (6.8° N) it climbs to 55° above the northern horizon at its highest; from Lethem (3.4° N), to 52° above the northern horizon. It is highest at midnight on the night of 29 Sep, in the middle of its season. The page works out tonight's rise, highest point and set for both towns in Guyana time (UTC-4), and where the Moon is.
What you'll see
- Your eyes: Not visible to the eye. It lies 8.3° north-west of Mirach.
- 10x50 binoculars: A faint smudge from a dark site. It lies 0.6° from the core of the Andromeda Galaxy.
- A small telescope (80 to 100 mm): A faint oval glow, larger and dimmer than M32, 0.6° north-west of the Andromeda Galaxy's core.
- A camera: Spans about 40% of an APS-C frame at 2,000 mm (field 0.7° × 0.4°); needs a tracking mount.
How big, how bright, how far
- Size on the sky: 16.2′ × 9.6′, 52% of the Moon's width (the Moon is about 31′ wide).
- Brightness: magnitude 8.2. Fainter than the faintest stars in Georgetown (4.3) and Lethem (6.0): binoculars or a telescope.
- Distance: 2.6 million light-years. The light reaching your eye left it about 2.6 million years ago.
- True size: 12,000 light-years across its catalogued outline; light crosses it in 12,000 years.
Apparent size from OpenNGC (Mattia Verga), CC-BY-SA-4.0.
What it is made of
- Type
- Dwarf elliptical galaxy
- Notable
- The 110th and final Messier object: Messier seems to have seen it with M31 and M32 but never listed it.
What is in it, not measured:
- Old stars: mostly old, yellow and red
- Very little cold gas or dust
- Dark matter: inferred from how its stars move
How we know: Distance from its brightest red giants (the tip of the red giant branch): NED-D (NASA/IPAC Extragalactic Database, redshift-independent distances), median of 14 TRGB estimates: 0.81 Mpc, 0.73-0.84 Mpc (16th-84th percentile); e.g. 2013AJ....146...86T, 2009AJ....138..332J, 2005MNRAS.356..979M; retrieved 2026-10-21. True size: the apparent size times the distance (apparent size: OpenNGC (Mattia Verga, CC BY-SA 4.0), commit 4e2398a2).
More deep-sky objects: Andromeda Galaxy (M31) · M32 (Galaxy) · Triangulum Galaxy (M33) · NGC 891 (Edge-on Galaxy) · NGC 7331 (Galaxy) · M74 (Phantom Galaxy)