M101 - Pinwheel Galaxy

This was my first long integration time galaxy target. I captured a total of 517 200" light frames across five nights from 4/18/2020 to 4/24/2020. The camera was a QHY183C at gain 16/offset 76 and the OTA was a AT72EDII (f/6) on an EQM-35 Pro mount. I ended up keeping a total of 410 light frames due to guiding issues on the first night for a total of 22.8 hours of total integration time. All were captured in my backyard which has B8 skies.

Flats were taken every night but only one set was used since my image train did not change throughout the capture dates.

Processing Details (All in PixInsight)

Calibration & Stacking

* Filter out high RMS subs manually

* WBPP script with "Calibrate Only" to calibrate & debayer each night's data

* Subframe Selector to filter and weight. Chose highest weight image as a reference

* StarAlignment

* ImageIntegration w/ Linear Fit clipping

* DrizzleIntegration (Scale=1, Drop Shrink=0.9, Kernel=vark1.5)

Processing

RGB (Initial Processing)

* DynamicCrop

* FastRotation to rotate 180deg for a more natural angle

* DBE (w/ 70 points @ 30 radius moved off of stars, tolerance=6, shadowsRelaxation=3, smoothing=0.7)

* BackgroundNeturalization

* PhotometricColorCalibration

* Extract L Channel

L Channel (Extracted from RGB)

* Extract star mask using StarNet++

* Deconvolution (using process from https://www.youtube.com/watch?v=6Maq-UkeqG8)

* PixelMath to add back in original stars

* TGVDenoise with a low contrast mask (Jon Rista method)

* MMT for noise reduction with a high attenuation mask (Jon Rista method, Luminance only)

* Arcsinh Stretch (x4)

* HDRMultiscaleTransform for handling the core brightness

RGB (Final Processing)

* RepairHSVSeparation Script to fix staturated stars

* TGVDenoise w/ a low contrast mask (Jon Rista method)

[li]MMTDenoise w/ a high attenuation mask (Jon Rista method, Chrominance and Luminance)

* Arcsinh Stretch (x3)

* Masked Stretch

* HistogramTransformation to bring in the black point

* MaskedStretch for additional stretch

* LRGBCombine with Chrominance Noise Reduction enabled

* CurvesTransformation for saturation boost

* SCNR to reduce green cast

* LocalHistogramEqualization for details

* MorphologicalTransform to reduce stars slightly

* CurvesTransformation for final tweaks