From March, 2021 the Dolphin-head Nebula

The Dolphin-head Nebula, aka Sharpless 2-308 aka the Cosmic Bubble, may be the most difficult object I’ve ever imaged. I shot four hours of five minute integrations in early March with my C11 and Hyperstar with a dual narrowband filter to accentuate the Hydrogen Alpha and Oxygen III. I could see the bubble in each individual frame but when I tried to process it the nebula would disappear. I eventually decided to wait until next winter and get more data. I could see that what I had was good but maybe just not enough.
Anyway, two and half months later I decided to take another crack at it. Starting from scratch with my 48 raw images, it worked. I was soon far beyond what I had achieved before. All this was in Photoshop. Once I had a reasonable image, I use a tool called Starnet++ which separates stars from extended objects like nebula. I then had one image of stars and one of nebula. I worked on the nebula, bringing out details, and then added it back to the stars image.
About the object, SH2-308 is a bubble blown by very hot Wolf-Rayet star in the constellation of Canis Major. The star is the one seen in the center of the bubble. Wolf-Rayet stars are very massive very hot stars that are thought to be pre-supernova. This one is about 5,000 light-years away and the bubble’s apparent size is slightly larger than the Moon. The “dolphin” is looking up to your left.
Thanks go to my friend John Reed for some ideas he gave me.

May 14, 2021 The Whirlpool Galaxy

I almost forgot about this. Several members of CAAS have already posted their shots of the Whirlpool Galaxy but here’s my first for the season. This was taken Thursday night at the River Ridge Observatory with my C11 at prime focus (2800mm) with an Optolong L-Pro light pollution filter. I used my ZWO ASI 294MC Pro one shot color, 30 2-minute images stacked with Deep Sky Stacker and then all subsequent processing with Photoshop.It needs more time for sure, maybe some with a filter to capture the H II regions but this turned out okay for the limited time spent on it.

5/14/2021 The Dumbbell Nebula

I shot this Thursday night at the River Ridge Observatory with my C11 at prime focus, all 2800mm of focal length. It’s 30 two minute images combined. This is the Dumbbell Nebula (aka Apple Core Nebula or Messier 27) in the constellation of Vulpecula (the little fox). It is a planetary nebula, one of the brightest, which are the remains of the extended atmosphere of all but dead stars called white dwarfs. The radiation from the very hot white dwarf excites the molecules in this nebula and causes it to glow. It is not symmetric because we are seeing it from the side and either the top and bottom of the apple or the two “bites” taken out of it represent the rotational axis of the white dwarf. I’m not sure which.