M106

Although it's a few hours fewer exposure time than [my last attempt at it](https://www.reddit.com/r/astrophotography/comments/b2w8dn/m106_14_hours_of_halrgb/), I'd consider this an improvement, mostly due to less light pollution and better post=processing skills. I love how much more visible the Ha 'tendrils' are in the core region of the galaxy compared to the old pic. Also made [an annotated version](https://i.imgur.com/hY2AorC.jpg), which highlights most of the galaxies in the background. Captured over 5 nights in 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/) 

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**[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- 92x120"

* R- 31x120"

* G- 31x120"

* B- 30x120"

* Ha - 51x300"

* 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

* EZ Decon (lum only)

* NoiseXTerminator (lum only)

* ArcsinhStrecth + HistogramTransformation to bring nonlinear

**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=0.12

* 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=2.5

**HaRGB:**

* Slight SCNR

* ArcsinhStretch + HistogramTransformations to stretch nonlinear

**Nonlinear:**

* LRGBCombination with stretched luminance

* Shitloads of CurveTransformations to adjust lightness, saturation, contrast, hues, etc.

* color saturation to slightly desaturate the Ha regions

* More curves/color saturation adjustments

* Extract L --> LRGBCombination for background chrominance noise reduction

* even more curves

* NoiseXTerminator

* MLT chroninance noise reduction

* UnsharpMask to further sharpen the galaxy details

* LocalHistogramEqualization

* EZ Star Reduction 

* noise generator to add noise back into star reduced areas

* Invert > SCNR > invert to remove magentas from the galaxy

* More curves

* MLT for large scale chrominance noise reduction

* guess what even more curves

* Resample to 70%

* Annotation