Bubblicious ...
Thursday November 7th & Tuesday November 12th were our club's (Buffalo Astronomical Association) imaging group (The Tuesday Night Imagers) imaging sessions at our club's dark sky observatory, The Beaver Meadow Observatory (BMO). Our club's Observatory Director and Tuesday Night ringleader ran the Celestron 14" Edge HD while another member ran the Tele Vue NP101is with his personal camera attached. I joined via Zoom. Of the two nights, the 12th had better seeing/transparency. The 7th was also plagued with software issues. They were not able to connect to the Pegasus Astro ultimate Power Box after a windows update. After several updates and reboots, the situation was resolved.
I have (and continue) to take PixInsight classes from Masters of PixInsight. Their most recent Photons to Photos class was on processing Bubble Nebula data from a Celestron 14" Edge. The timing was perfect. I picked up a few techniques that were ultimately used to process this image. Here is the result.
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| NGC 7635 - The Bubble Nebula from 10/7 & 10/12 at the BMO. |
Processing:
All pre and post processing was performed in PixInsight. Pre-Processing: Our club's Observatory Director pre-processed the images in PixInsight (WBPP) and sent me the Master Light image. Linear Post Processing: Background extraction was performed with Auto DBE Script from Seti Astro followed by BXT (correct only). SPCC was used for Color Calibration followed by a full application of BXT. The Stars were removed using StarXT. Starless Linear: Noise was reduced with NXT. The image was made non-linear with HT. Starless Non-linear Post Processing: The CreateHDRImage script was used to compress the Bubble and bright surrounding nebula (a mask was created and used by the script). Narrowband Normalization (Mode 1) was used to create the SHO or Hubble Palette look. Saturation and intensity were increased with CT. Sharpness was improved with ImageBlend script using a High Pass Filter. LHE was applied at 2 Kernel sizes. Additionally, Unsharp mask was applied. Finally, the DarkStructureEnhance script was applied (0.2). Stars Linear: The Stars image was made non-linear with Seti Astro's Star Stretch script. Stars Non-Linear: Saturation was increased with CT. Starless: Intensity, and contrast were adjusted with various applications of CT. The Stars and Starless images were combined with Pixel Math to produce the final image.
What is it?
NGC 7635 is also known as Sharpless 162, Caldwell 11, and The Bubble Nebula. It is an H II region emission nebula in the constellation of Cassiopeia. The Stellar Wind from a young, massive, and hot central star has created the bubble by blasting it out of the glowing gas against the denser material in the surrounding molecular cloud.
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| Annotated image of NGC 7635 - The Bubble Nebula. |
How Big is it?
NGC 7635 has a size of 15.0 x 8.0 arcminutes (1 degree is 60 arcminutes) on the night sky. It is about 6.1 light years in diameter (similar in size to our Milky Way Galaxy).
How Far is it?
NGC 7635 is located about 11,000 light-years (ly) from Earth.
How to find it?
The NGC 7635 is located about halfway between Cassiopeia and Cepheus, very close to the Open Star cluster Messier 52 (M52). Dark skies, large aperture, and a nebula filter are helpful in viewing this group.
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| Finder Chart for NGC 7635, The Bubble Nebula. |
