Location & Date	Backyard, Abbott Observatory- Long Island, NY,  October & November 2020
Telescope	TMB130SS F/7 APO, Moonlite focuser, Losmandy G11 Gemini Image scale 1.54 arcsec/pixel
Camera	SBIG ST-10XME Baader  Ha OIII 5nm  filters CCD temp -15°C
Exposures	Ha-18x15m  OIII-18x 15m    Bin 1x1 per each 12 mosaic panel Moon -  Ha  1x.001 sec  single frame
Planning & Acquisition	Mosaic planning - Sequence Generator Pro Mosaic Tool Image acquisition - Sequence Generator Pro w/PinPoint & PHD2 (guiding)
Processing	CCDStack - calibration, debloom Astro Pixel Processing -  Normalize, Alignment, Combine, mosaic stitching Adobe Photoshop -  Ha + OIII combine, Noise reduction, JPEG conversion This is a 12 panel bicolor mosaic using mapped colors of  Ha (red) + OIII (blue)  and a synthetic green ( Ha + OIII)

   SH2-216 is a very dim planetary nebula in the constellation Perseus and is the largest planetary in our sky measuring about 1.6 angular degrees and is over 3 times the size of our moon which measures 0.5 angular degrees. Hover over the image above to get the exact camera scale between the moon and nebula. With a distance of approximately 420 light years this is one of the closest planetary nebula to our galaxy. The dim surface brightness and large size is due to its age and diffusion. Planetary nebulas are formed when a dyeing star expels shells of ionized gas that when viewed, they have a roundish appearance like a planet. These nebula leave behind a very dense hot star called a white dwarf.

Per SIMBAD, the SH2-216 white dwarf star is ALS 8032 and is highlighted in the mouse over image link above. 

  This was a very challenging target due to its low surface brightness.  Even using a camera with the very high QE KAF-3200 CCD I needed at least 4.5 hours of exposures for each of the 12 panels totaling 54 hours to get a decent Hydrogen-alpha (Ha) image. Oxygen (OIII) was barely visible in only a few frames. Total integration time of Hydrogen and Oxygen is 108 hours. Due to the size of the mosaic being 12 panels, my old dual core supporting only 2 threads and 16G of RAM PC wasn't up to processing the large number frames in a reasonable amount of time, so I upgraded to a more powerful Intel 6 core processor able to run with 12 threads plus 64G of RAM desktop. This made a huge improvement in processing the over 100 frames for each layer in a short amount of time. Astro Pixel Processor software made creating a mosaic less time consuming and did an excellent job with normalizing and aligning each mosaic panel with nicely blended seams.  Ha and OIII data was used to create the RGB image so not all the star colors are accurate.

This is the mosaic panel created by Sequence Generator Pro's mosaic tool.

Each frame overlaps its neighbor by 10% to allow the seams to blend.

Sequence Generator Pro calculated and assigned each frames RA & DEC coordinates to each panel.

The entire imaging session was automated. All I had to do was select the start and end times for each night and hoped that the clouds didn't arrive.

The bottom panels 5, 10 & 15 contained only stars hence were not imaged.