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The Pacman Nebula

A cloud of hydrogen lit from inside by young stars, with a lane of dust bitten out of the front of it.

NGC 281, a rounded red nebula with a dark notch cut across it, set in a rich field of stars. — Photographed by TPN Explorer from Tilton on the Hill in Leicestershire in the early hours of 23 August 2026, with a Dwarf 3 and an astro filter. 80 frames of 60 seconds, 1 hour 20 minutes. Tap the picture for a larger version.

Seeing it from the UK

It sits in Cassiopeia, the W shape, which never sets from the UK and rides high on autumn and winter evenings, so it is available for months on end. It is not something to look for with your eyes. Even in a decent telescope it is a very faint grey patch, and the red never appears because human eyes do not see colour at that brightness. It is a camera object, and it wants a dark sky and a filter that passes hydrogen. From September to February it is high enough to be worth pointing at almost any clear night.

This is a nursery. The red glow is hydrogen gas being lit up by a handful of very young, very hot stars sitting in the middle of it, and those stars formed out of the same cloud within the last few million years. On the scale of the things on this page that is practically this morning.

The nickname comes from the dark notch. It is not a hole in the cloud, it is dust in front of the glowing gas, blocking the light behind it in the shape of a mouth. Dust like that is ordinary in star forming regions, and it is the raw material that ends up in planets.

The small cluster of stars at the centre is catalogued as IC 1590. Their light is what makes the gas glow at all, and the same light is slowly eroding the cloud that made them, so this object is destroying itself as it goes.

It is far off compared with most of what you can photograph on one night: around nine and a half thousand light years, right across a spiral arm of our own galaxy from us.

The numbers

Also called: NGC 281, and Sharpless 184
Constellation: Cassiopeia, the W
Distance: About 9,500 light years
What it is: A hydrogen cloud with young stars forming inside it
The cluster lighting it: IC 1590, a few million years old
The dark notch: Dust in front of the glowing gas, not a gap in it
Visible to the eye: No, it is a photographic target
Best months from the UK: September to February

To find out whether it is up tonight, and when it gets properly dark where you are, see Sky Tonight.