NGC 7000 is an emission nebula about 2600 light years away in the constellation Cygnus. This is a false color image taken through [sulfur, hydrogen, and oxygen filters](https://i.imgur.com/bFv1VCg.png) that were then mapped to red green and blue channels respectively to make a color image. This is used to help highlight the different ionized gases, as in [true color photos](https://c1.staticflickr.com/5/4812/46335334442_bda5168027_o.png) the dominant hydrogen gas makes the whole nebula look red.
This is a [3 panel mosaic image](https://i.imgur.com/Hz2eMBX.png) I shot over the course of ~16 months. I had originally shot the [right panel](https://www.reddit.com/r/astrophotography/comments/gauicq/the_cygnus_wall_in_sho/) back in April 2020, and the [top left panel](https://www.reddit.com/r/astrophotography/comments/pu62xw/north_america_nebula/) in August/September 2021. I saw they overlapped some so I got some data on the bottom left panel to make a more cohesive mosaic of the region. I didn't get around to processing it until now because ~~I'm lazy~~ pixinsight refuses to mosaic these images cleanly for some reason. Huge thanks to /u/EasyQuest for showing my your mosaic technique with ICE. Because I moved in 2020 to an area with less light pollution, there is some noticeable border with the signal to noise ratio between the panels. Due to the varying rotations i had to do a heavy crop on the image overall. I also [ran it through starnet to make a starless version for the hell of it](https://i.imgur.com/DQoHoRQ.jpg).
Captured over 16 nights from April 2020 through September 2021. Right panel from Bortle 7 light pollution (downtown Athens, GA) and the left two panels from Bortle 6 suburbs.
**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:** 36 hours 12 minutes (Camera at Unity Gain, -15°C)
* **Right Panel**: 5h 30m
* Sii- 19x360
* Ha- 18x360"
* Oiii- 18x360"
* **Top Left:** 15h 12m
* Sii- 52x360
* Ha- 44x360"
* Oiii- 56x360"
* **Bottom Left:** 14h 36m
* Sii- 54x360
* Ha- 35x360"
* Oiii- 57x360"
* 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)
**Creating the Mosaic:**
> For whatever reason mosaic by coordinates refused to work for me despite updating/reinstalling pixinsight, or even downloading the script directly from others.
* DynamicCrop to remove stacking artifacts
* Several rounds of automatic and dynamic background extractions to remove gradients
* LinearFit
* Exported photos as tiff, stitched in Microsoft ICE per filter
* CloneStamp to remove artifacts from the Sii mosaic
**Linear:**
* DynamicCrop
* EZ Decon/Denoise
* STF stretch via HistogramTransformation to bring each image nonlinear
**Nonlinear:**
* PixelMath to map SHO images to RGB
* Extract L > LRGBCombination for chrominance noise reduction
* Invert > SCNR > invert to remove magentas from stars and partially from the background
* Shitloads of CurveTransformations to adjust lightness, saturation, contrast, hues, etc.
* MultiscaleLinearTransform noise reduction
* EZ Star reduction
* NoiseGenerator to add noise into reduced star areas
* LocalHistogramEqualization
* HistogramTransformation for lightness adjustments
* ColorSaturation to further tweak star color (was still extremely red)
* CloneStamp to remove a few weird looking stars
* Content aware fill in Photoshop to fill in a small part of a corner that the mosaic didn't cover (I know, I sinned)
* Even more curves
* Integer Resample to 50%
* Annotation
lefty7283
