Antennae Galaxies (NGC 4038 and NGC 4039)
Two galaxies in Corvus caught in a collision, about 70 million light-years away. Long, antenna-like arms of stars thrown out by the crash give them their name.
Galaxy in Corvus. Magnitude 10.2.
Can you see it from Guyana?
From Georgetown (6.8° N) it climbs to 64° above the southern horizon at its highest; from Lethem (3.4° N), to 68° above the southern horizon. It is highest at midnight on the night of 20 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 3.6° west of Gienah.
- 10x50 binoculars: Just detectable in binoculars from a dark site, as a faint smudge.
- A small telescope (80 to 100 mm): Two faint, touching glows like a comma; the long tails are a camera target.
- A camera: Tiny on camera: it needs 2,000 mm or more of focal length on a tracking mount. The photo above shows the two cores; the long tails need a wider frame.
How big, how bright, how far
- Size on the sky: 5.4′ × 3.8′, 17% of the Moon's width (the Moon is about 31′ wide).
- Brightness: magnitude 10.2. Fainter than the faintest stars in Georgetown (4.3) and Lethem (6.0): binoculars or a telescope.
- Distance: 70 million light-years. The light reaching your eye left it about 70 million years ago.
- True size: 110,000 light-years across its catalogued outline; light crosses it in 110,000 years.
Apparent size from OpenNGC (Mattia Verga), CC-BY-SA-4.0.
What it is made of
- Type
- Pair of colliding galaxies
What is in it, not measured:
- Stars: many of them young
- Plenty of gas: fuel for new stars
- Dark matter: inferred from how its gas moves
How we know: Distance from Cepheid variable stars and its brightest red giants (the tip of the red giant branch): NED-D (NASA/IPAC Extragalactic Database, redshift-independent distances), median of 13 Cepheids/TRGB estimates: 21.50 Mpc, 17.76-21.60 Mpc (16th-84th percentile); e.g. 2017ApJ...836...74J, 2016ApJ...826...56R, 2015ApJ...807..133J; 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: Sombrero Galaxy (M104) · M61 (Galaxy) · Southern Pinwheel Galaxy (M83) · M49 (Galaxy) · Centaurus A (NGC 5128) · M58 (Galaxy)