Imaged M31, the Amdromeda Galaxy, on the nights of November 13/15/16/18 and December 7/8/11, 2020. Image was captured using an APO refractor and full spectrum modified DSLR through a dual narrowband filter. My original intent was to collect OSC RGB data using a IDAS LPS-D1 clip filter, but forgot the Optolong LEnhance 2" filter was mounted in the field flattener, so I ended up with 10+ hours of NB data. Maybe next year I'll finally get a nice collection of RGB data for M31... The NB data turned out pretty nice, so here it is...
Imaged with WO GT81 at F4.7 (382 mm focal length) using Flat6A II field flattener/0.8x reducer, Optolong L-Enhance dual narrowband filter (and IDAS LPS-D1 clip filter), and full spectrum modified Nikon D5300. Total integration time of ~13 hours using 194 subs at ISO200x240 sec.
Pre-processed using PixInsight Batch Pre-Processing (BPP) script. Images calibrated using darks, flats, and flat darks. Extracted red/green/blue channels using BatchChannelExtraction script. R and G+B channels registered and stacked using StarAlighment, Integration, and Drizzle Integration. R and G+B channels individually post-processed in Pixinsight. Initial processing: Cropped, gradient removal with ABE. Noise reduction using EZ Processing Suite for PixInsight EZ Denoise (Reference:
https://pixinsight.com/forum/index.php?threads/ez-processing-suite.14937/). Additional post-processing in PixInsight: masked stretch, curves transformation, local histogram transformation, and morphological transformation. Color image generated using SHO-AIP script in PixInsight (Luminance image combined Ha and OII data using 'lighten'; Channel mix: R=100%Ha, G=50%Ha+50% OIII, B= 100%OIII). Final noise reduction and mild sharpening using Topaz Studios DeNoise AI.
Original version = Color image from NB data
Rev B = Ha data
Rev C = OIII data
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