This thing is low surface brightness alright. could definitely have benefitted from being shot under darker skies, but I worked with what I could get from my driveway. Captured over 6 nights in April/May, 2022 from a Bortle 6 zone
**Places where I host my other images:**
[Instagram](https://www.instagram.com/leftysastrophotography/) | [Flickr](https://www.flickr.com/people/leftysastrophotography/)
---
**[Equipment:](https://i.imgur.com/ejpKkwU.jpg)**
* TPO 6" F/4 Imaging Newtonian
* Orion Sirius EQ-G
* ZWO ASI1600MM-Pro
* Skywatcher Quattro Coma Corrector
* ZWO EFW 8x1.25"/31mm
* Astronomik LRGB+CLS Filters- 31mm
* Astrodon 31mm Ha 5nm, Oiii 3nm, Sii 5nm
* Agena 50mm Deluxe Straight-Through Guide Scope
* ZWO ASI-290mc for guiding
* Moonlite Autofocuser
**Acquisition:** 18 hours 48 minutes (Camera at Unity Gain, -20°C)
* L- 148x120"
* R- 64x120"
* G- 49x120"
* B- 57x120"
* Ha - 82x300"
* Darks- 30
* Flats- 30 per filter
**Capture Software:**
* Captured using [N.I.N.A.](https://nighttime-imaging.eu) and PHD2 for guiding and dithering.
**PixInsight Processing:**
* BatchPreProcessing
* SubframeSelector
* StarAlignment
* [Blink](https://youtu.be/sJeuWZNWImE?t=40)
* ImageIntegration
* DrizzleIntegration (2x, Var β=1.5)
**Linear:**
* DynamicCrop
* DynamicBackgroundExtraction
* NoiseXTerminator (lum only)
* MaskedStretch to 0.1 background
* Starnet++ starmask made, subtracted from 0.3 Gray image and colvolved
* Previous image used as a mask to stretch nebulosity without stretching stars
* Normal HistogramTransformation
**RGB:**
* Channelcombination to combine monochrome images into RGB image
* PhotometricColorCalibration
* SCNR green
* HSV Repair
**Adding Ha:**
> I followed this tutorial which had great results on some [prior](https://www.reddit.com/r/astrophotography/comments/q8ogec/m33_the_triangulum_galaxy_in_halrgb/) HaLRGB [galaxy pics](https://www.reddit.com/r/astrophotography/comments/ml2os3/m51_the_whirlpool_galaxy_in_halrgb/):
> http://www.arciereceleste.it/tutorial-pixinsight/cat-tutorial-eng/85-enhance-galaxy-ha-eng
* PixelMath to make Clean Ha. This effectively [isolates just the Ha regions](https://i.imgur.com/Aob3UEO.png) from the red continuum spectrum
> Ha-Q * (Red-med (Red))
> Q=0.15
* PixelMath to combine Clean Ha
* PixelMath to add Ha to RGB image ($T)
> R= $T+B*(Ha_Clean - med(Ha_Clean))
> G= $T
> B= $T+B\*0.2*(Ha_Clean - med(Ha_Clean))
> B=2
**HaRGB:**
* ArcsinhStretch + HistogramTransformations to stretch nonlinear
**Nonlinear:**
* Curves to saturate the galaxy
* color saturation to slightly desaturate the Ha regions (they got boosted a little too much)
* LRGBCombination with luminance
* NoiseXTerminator
* Shitloads of CurveTransformations to adjust lightness, saturation, contrast, hues, etc.
* several rounds of MLT for luminance and chrominance noise reduction
* more curves
* EZ Star Reduction
* noise generator to add noise back into star reduced areas
* Extract L --> LRGBCombination for background chrominance noise reduction
* Slight SCNR
* more curves
* Resample to 70%
* Annotation
lefty7283
