Imaged M33, the Triangulum Galaxy, on the nights of December 7-11, 2020 (must be my record for consequtive cloudless nights!). Image was captured using an APO refractor and full spectrum modified DSLR through a dual narrowband filter. Kinda funny story, 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 (and somehow failed to figure out why the histograms were so low for RGB images!), so I ended up with 10+ hours of NB data, oh well...
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 ~12 hours using 189 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. NB-RGB version generated using SHO-AIP script in PixInsight (Luminance image combined Ha and OII data using 'lighten'; Channel mix: R=50%HA + 50%original R, G=25% OIII + 75% original G, B= 25%OIII + 75% original B). Final noise reduction and mild sharpening using Topaz Studios DeNoise AI.
Original version = NB-RGB combined image
Rev B = Ha data
Rev C = OIII data
RGB image:
https://astrob.in/ll4tqw/0/
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