Seagull Nebula (IC 2177)
A long glowing cloud in Monoceros, about 200 arcminutes across. Its head is a small nebula round the star HD 53367; the wings are a far larger arc of glowing hydrogen.
Reflection nebula in Monoceros.
Can you see it from Guyana?
From Georgetown (6.8° N) it climbs to 73° above the southern horizon at its highest; from Lethem (3.4° N), to 76° above the southern horizon. It is highest at midnight on the night of 4 Jan, 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 7.8° north-east of Sirius.
- 10x50 binoculars: Hard: only the head shows, from a dark site.
- A small telescope (80 to 100 mm): Too big for most telescope fields; the head around its star is the part to look for.
- A camera: Spans about 40% of an APS-C frame at 135 mm (field 9.9° × 6.6°); needs a tracking mount.
How big, how bright, how far
- Size on the sky: 200′, 6.4 Moons across (the Moon is about 31′ wide).
- Distance: 4,000 light-years. The light reaching your eye left it about 4,000 years ago.
- True size: 210 light-years across its catalogued outline; light crosses it in 210 years.
What it is made of
- Type
- Emission and reflection nebula
What is in it, not measured:
- Ionised hydrogen: the red wings, Sh2-296
- Dust: lit by the star HD 53367 in its head, Sh2-292
- Young stars: of the Canis Major R1 group
How we know: Distance from Gaia parallaxes of the young stars of Canis Major R1, the group it lights: Santos-Silva et al. 2021, MNRAS 508, 1033 (arXiv:2108.06234), Table 2: CMa R1 1,099 ± 29 pc; the four CMa OB1 groups lie at 1,005-1,229 pc. True size: the apparent size times the distance (apparent size: Sharpless 1959, ApJS 4, 257 (VizieR VII/20), Sh2-296).
More deep-sky objects: Thor's Helmet (NGC 2359) · Hubble's Variable Nebula (NGC 2261) · M78 (Reflection Nebula) · Horsehead Nebula (Barnard 33) · Flame Nebula (NGC 2024) · De Mairan's Nebula (M43)