The Horsehead Nebula is a dark nebula about 1400ly away from us in the constellation Orion. The Bright star near it is Alnitak, [and it one of the stars that makes up Orion's Belt](https://i.imgur.com/aAghUNS.png). Because this is one of the brightest stars that people photograph when shooting DSOs, it often can result in [unwanted halos](https://i.imgur.com/Wx0zStT.png), which are present in my RGB filters. I was able to edit the halos out to a level I felt was acceptable (see processing info below), however there still is some color fringing/artifacts on the edge of the halos. Also the bottom left of Alnitak is the Flame Nebula, which is just a nebula that happens to be in the foreground to the horsehead. Captured over 5 nights from February 14-20, 2022 from my Bortle 6 driveway.
**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-120mc for guiding
* Moonlite Autofocuser
**Acquisition:** 12 hours 6 minutes (Camera at Unity Gain, -20°C)
* Lum- 251x60"
* Ha- 67x300"
* Red- 33x90"
* Green- 31x60"
* Blue- 29x60"
* 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
* Automatic and Dynamic Background extractions
**RGB:**
* ChannelCombination to map monochrome R, G, and B images into a color image
* PhotometricColorCalibration
* Slight SCNR green
* HSV repair
* ArcsinhStretch + HistogramTransformation to bring nonlinear
**Luminance:**
* PixelMath to combine Ha and luminance stacks to make super-luminance image (to be used as the luminance layer going forward)
> 0.7\*Ha + 0.3\*Lum
* EZ Decon
* NoiseXTerminator
* ArcsinhStretch + HistogramTransformation to bring nonlinear
**Nonlinear:**
* Created two circle masks per [this guide](https://digitalstars.wordpress.com/2019/10/27/tutorial-how-to-eliminate-star-halos-in-pixinsight/). SCNR + curve tweaks to mitigate the halos from my RGB filters
* LRGBCombination with SuperLum
* Ungodly amounts of curve transformations to further mitigate the halos, as well as just general curves for lightness, saturation, contrast, hues, etc.
* ColorSaturation
* Extract L > LRGBCombination for chrominance noise reduction
* LocalHistogramEqualization
* EZ Star reduction
* NoiseGenerator to add noise into reduced star areas
* another round of LHE
* more curves
* CloneStamp to remove a couple of weirdly artifacted stars
* even more curves
* Resample to 60%
* Annotation
lefty7283
