Ha-RGB Bubble Nebula with 460EX, C-8 EdgeHD

[topboxman]

Seeing conditions during imaging RGB appeared to be not so good due to bloated stars. I refocus for every filter change because I noticed the center spike with Bahtinov mask shifts slightly with different filters even with Astrodon filters. Probably the focus shift is more noticeable at 2000mm focal length or slow focal ratio of F/10.

I used special PixInsight HaRGB combination tool to process this image. It worked pretty well. All processing was done with PixInsight.

NGC7635: Bubble Nebula in Cassiopeia. 8/24/2012 (Ha) and 9/15/2012 (RGB)
Astrodon Ha 5nm filter: 21 x 15 minutes, 1x1, Excellent seeing condition
Astrodon Red: 8 x 10 minutes, 1x1, Less than ideal seeing condition
Astrodon Green: 8 x 10 minutes, 1x1, Less than ideal seeing condition
Astrodon Blue: 8 x 10 minutes,  1x1, Less than ideal seeing condition

Celestron 8" EdgeHD at F/10 with A-P Mach1GTO GEM. Atik 460EX mono. Hutech OAG. Lodestar.
Captured and pre-processed with Nebulosity. Stacked and post processed with PixInsight.
PHD settings: RA Aggressiveness: 90, RA Hysteresis: 10, Max Dec Duration: 75, Min Motion: 0.70, Calibration Steps: 125msec, Auto/Resist Switching, Extreme dithering and Settled at < 0.5, 3 - 4 sec guiding exposure.

Red = Ha + Red, Green = Green, Blue = Blue

http://peternagy.smugmug.com/Telescopes/Nebulae/15823498_3vBdTQ#!i=2099824883&k=cjWhMxF

Click on the image to zoom.

Peter

[MikeM]

Hi Peter, aside from the issue you had with the stars it's quite the nice image.

[topboxman]

Thanks Mike. This is my first time imaging and processing from a mono camera with LRGB and NB filters. I must have reprocessed this about a hundred times and I think I'm done for now and start imaging other DSOs. I thought Bubble Nebula was a good place to start since it has strong narrow band signals and good DSO size at 2000mm focal length.

Peter

[topboxman]

I modified my original post to say that I figured out how to process Ha with RGB by using PixInsight HaRGB script and works pretty well. The star colors came out pretty good.

Peter

[chrisjbaileyuk]

the PI HaRGB script is very useful and works very well in my experience.