Pacman Nebula (NGC 281)
A glowing cloud of hydrogen in Cassiopeia, lit by IC 1590, a cluster of young stars inside it. A dark lane of dust bites into its round outline, which gives it the Pacman name.
Emission nebula in Cassiopeia.
Can you see it from Guyana?
From Georgetown (6.8° N) it climbs to 40° above the northern horizon at its highest; from Lethem (3.4° N), to 37° above the northern horizon. It is highest at midnight on the night of 2 Oct, 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 1.7° east of Schedar.
- 10x50 binoculars: Hard: a faint glow from a dark site, best with a nebula filter.
- A small telescope (80 to 100 mm): A faint glow around a small group of stars; a UHC or OIII filter shows the dark notch of the Pacman.
- A camera: Spans about 40% of an APS-C frame at 1,000 mm (field 1.3° × 0.9°); needs a tracking mount. An H-alpha-sensitive (modified) camera brings out its red glow.
How big, how bright, how far
- Size on the sky: 35′ × 30′, 1.1 Moons across (the Moon is about 31′ wide).
- Distance: 8,800 light-years. The light reaching your eye left it about 8,800 years ago.
- True size: 90 light-years across its catalogued outline; light crosses it in 90 years.
Apparent size from OpenNGC (Mattia Verga), CC-BY-SA-4.0.
What it is made of
- Type
- Emission nebula with a young cluster
- Mass
- About 1,100 times the Sun's mass, in the stars of its cluster IC 1590
- Age
- About 12 million years (range 6.9 million years to 20 million years), the age of IC 1590
What is in it, not measured:
- Ionised hydrogen: glows red where hot stars light it
- Helium and heavier gases: with traces of oxygen, nitrogen and sulphur
- Dust: in dark lanes
- Young hot stars: that light it
How we know: Distance from Gaia parallaxes of the stars of IC 1590, the cluster inside it: Hunt & Reffert 2024, A&A 686, A42 (Gaia DR3 cluster catalogue, VizieR J/A+A/686/A42), retrieved 2026-10-21: IC 1590 2,707 pc; statistical 8,775-8,882 ly (16th-84th percentile); Gaia DR3 parallax zero-point systematics (about 0.02 mas) add about 5%. True size: the apparent size times the distance (apparent size: OpenNGC (Mattia Verga, CC BY-SA 4.0), commit 4e2398a2). Mass: Hunt & Reffert 2024, A&A 686, A42 (Gaia DR3 cluster catalogue, VizieR J/A+A/686/A42), retrieved 2026-10-21, IC 1590: total 1,046 ± 157 Suns.
More deep-sky objects: Little Dumbbell Nebula (M76) · Bubble Nebula (NGC 7635) · Cave Nebula (Caldwell 9) · Blue Snowball Nebula (NGC 7662) · Cat's Eye Nebula (NGC 6543) · Crescent Nebula (NGC 6888)