SAS Astronomy Pictures of the Month [December, 2025]
Pacman, Flip-Flop and a Propeller!
On the left: IC281 the Pacman nebula in Cassiopeia: ASI 2600 MM HOOS NB + Lum taken with C6 f/10 7.5 hrs total.
On the right: Pacman composite of the image on the left with a wider field OSC image taken with a William Optics FS98 f/6.3 refractor 90 min
IC281 – The Pacman Nebula by David Murray
This is a pretty small galaxy (3.2′ x 2.5′), so I was pretty happy with the result. Sometimes referred to as the Propeller Galaxy, NGC7479 in Pegasus is a barred spiral galaxy about 105 million light years away. It is a Seyfert galaxy, with bursts of star formation throughout its structure, including its nucleus, arms and central bar. Oddly, the arms observed in the radio spectrum appear to rotate in the opposite direction to those in the visible and near IR. This is thought to be a result of a merger with a smaller companion about 300 million years ago.
This image is a stack of 192 3min exposures (about 9.6h) taken over several nights using my ASI2600mc on a 12 inch Meade SCT and MyT Paramount. I processed the image using DeepSkyStacker for stacking and Pixinsight / GIMP for post processing.
Propeller Galaxy in Pegusus – by Terry Riopka
Here’s an update on this interesting planetary with my 12 inch scope. In apparent size, it’s about the size of the core bulge in the Propeller galaxy above. It’s one of the few planetaries in Cassiopeia, located about 4200 light years away. It’s estimated to be about 10,000 years old with a ring-like structure superimposed on a spheroidal fainter component. Visually, this planetary has also been observed to seem to flip orientation when switching from averted to direct vision, hence its name. Here’s my original version with my 10 inch oh so many years ago. It’s fun flipping back and forth between my most recent version and the 10inch version… You can see analogous structure in both, though obviously of different resolution. Damn, my focus in my altazimuth 10inch version was good!
This image is a stack of 266 3min exposures (about 13.3h) taken over several nights using my ASI2600mc on a 12 inch Meade SCT and MyT Paramount. I processed the image also using DeepSkyStacker for stacking and Pixinsight / GIMP for post processing.
IC289 – The Flip Flop Nebula in Cassiopeia, by Terry Riopka