NGC 281 (Emission Nebula) and IC 1590 (Open Cluster) in Cassiopeia
The PacMan Nebula
From the deck of my house, observing dim non-Messier Emission Nebula can be a
challenge, due to the light pollution from the surrounding suburbs. Nebula filters are
often necessary for success.
However, seeing the PacMan Nebula (NGC 281) is easier than many amateurs realize.
This large (Full Moon size) nebula is not difficult to see with binoculars, even without
filters, from a dark site. Stephen O’Meara has observed it visually (see his write-up in
his “Hidden Treasures” book), a feat that I have never succeeded doing. But the nebula
is bright enough that from my house with the 6-inch refractor I can catch glimpses of the
nebula, without a filter, using a wide-field, low-power eyepiece. If I add an Oxygen III filter
or UHC filter, the nebula pops into view.
In the middle of the nebula shines a bright star (HD 5005). If you up the power on this
star you will discover that it is embedded in a cluster of dimmer stars (Open Cluster -- IC
1590). This bright O5-type star and its neighbors are responsible for fueling the glow of
the PacMan Nebula; much like what the Trapezium-stars do for the Orion Nebula.
In Kanipe and Webb’s new “Annals of the Deep Sky – Volume 4”, they provide an
interesting discussion about the possibility that the PacMan Nebula was created/pushed
away from the mid-plane of the Milky Way’s Perseus arm riding the expanding edge of a
Supernova Bubble created 17 million years ago. The age of the nebula proper is 3.5
million years while the IC 1590 cluster is only a million years old. It took a long time to
create this interesting collection of celestial objects. It is well worth your time to visit and
enjoy the view.