It wasn't until I was processing the pic that I found out there's a quasar right next to the nebula. KUV 18217+6419 is one of the brightest quasars, and at ~3.7 Billion light years away, it's the most distant thing I've ever photographed. Captured over a bunch of nights from October through December, 2023 from a Bortle 9 zone.

Places where I host my other images:

Flickr | Instagram

Equipment:

• 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: 63 hours 18 minutes (Camera at unity gain, -15°C)

• Ha - 252x600"

• Oiii - 112x600"

• Red - 53x60"

• Green - 54x60"

• Blue - 51x60"

• Darks- 30

• Flats- 30 per filter

Capture Software:

• Captured using N.I.N.A. and PHD2 for guiding and dithering.

PixInsight processing:

Preprocessing

• BatchPreProcessing

• StarAlignment

• Blink

• ImageIntegration per channel per panel

• DrizzleIntegration (2x, Var β=1.5) per panel per channel

Narrowband Linear:

• DynamicBackground Extraction

duplicated each image and removed stars via StarXterminator. Ran DBE with a shitload of points to generate background model. model subtracted from original pic using the following PixelMath (math courtesy of /u/jimmythechicken1)

$T * med(model) / model

• Tried doing BlurXTerminator here but there isn't much structure to sharpen

• Completely removed stars from narrowband images

• NoiseXterminator

• EZ Soft stretch to bring nonlinear

RGB linear

• DynamicBackground extraction as above

• ChannelCombination to combine R G and B stacks into color image

• SpectroPhotometricColorCalibration

• HSV Repair

• StarXterminator to make stars-only pic

• ArcsinhStretch + HT to bring nonlinear

• SCNR > invert > SCNR >invert to remove greens and magentas from stars

• Stars only pic saved for later addition to starless pic

Nonlinear:

• StarX to remove all stars

• PixelMath to create color image from the Ha and Oiii images using /u/dreamsplease's palette

  R = iif(Ha > .15, Ha, (Ha*.8)+(Oiii*.2))

  G = iif(Ha > 0.5, 1-(1-Oiii)*(1-(Ha-0.5)), Oiii *(Ha+0.5))

  B = iif(Oiii > .1, Oiii, (Ha*.3)+(Oiii*.2))

• BackgroundNeutralization

• shitloads of CurveTransformations to adjust hue, lightness, saturation, etc. (some with lum masks)

• more NoiseXTerminator

• Extract L --> LRGBCombination for chrominance noise reduction

• More curves

• MLT noise reduction

• LocalHistogramEqualization

• Relinearized narrowband and stars images to add in the stars only image

"unstretched" both images with histogramtransformation midtones set to 0.9999

pixelmath to just add those two images together

histogramtransformation to un-relinearize them by setting midtones to 0.0001

• Final Round of BXT to sharpen the stars a little

• Resample to 70%

• DynamicCrop

• Annotation