M105 (Galaxy)
A round elliptical galaxy in Leo, in the Leo I group with M95 and M96. Its smooth light once made it a standard for measuring how galaxies fade from centre to edge.
Galaxy in Leo. Magnitude 9.3.
Can you see it from Guyana?
From Georgetown (6.8° N) it climbs to 84° above the northern horizon at its highest; from Lethem (3.4° N), to 81° above the northern horizon. It is highest at midnight on the night of 2 Mar, 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 9.7° east of Regulus.
- 10x50 binoculars: Just detectable in binoculars from a dark site, as a faint smudge.
- A small telescope (80 to 100 mm): A small, round glow with a bright centre; NGC 3384 is close by and M96 0.8° to the south.
- A camera: Tiny on camera: it needs 2,000 mm or more of focal length on a tracking mount.
How big, how bright, how far
- Size on the sky: 4.9′ × 4.3′, 16% of the Moon's width (the Moon is about 31′ wide).
- Brightness: magnitude 9.3. Fainter than the faintest stars in Georgetown (4.3) and Lethem (6.0): binoculars or a telescope.
- Distance: 40 million light-years. The light reaching your eye left it about 40 million years ago.
- True size: 53,000 light-years across its catalogued outline; light crosses it in 53,000 years.
Apparent size from OpenNGC (Mattia Verga), CC-BY-SA-4.0.
What it is made of
- Type
- Elliptical galaxy
- Notable
- It was used as a standard for galaxy brightness profiles because its light is so smooth, though closer study found it less smooth than first thought.
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 11 TRGB estimates: 11.50 Mpc, 10.26-12.44 Mpc (16th-84th percentile); e.g. 2016ApJ...822...70L, 2007ApJ...666..903H, 2004AJ....127.1441G; 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: M96 (Galaxy) · M95 (Galaxy) · M98 (Galaxy) · Coma Pinwheel (M99) · M100 (Galaxy) · M84 (Galaxy)