IMO the ‘heart’ looks more like a chode with huge balls

This is my most ambitious astrophotography project yet, coming in at over 110 hours 18 minutes of total exposure time (albeit across 12 panels), beating out my previous record of 101 hours on the Elephant Trunk Nebula

The 12 panel mosaic ended up being 518 megapixels in size after cropping, and was an absolute bitch to process. probably never gonna do a mosaic this big again unless I have some quantum supercomputer. I don’t have any way to reliably host this on my flickr page, so the image you’re seeing is a 2X downsample.

Captured over 35 nights from October 2022 through March 2023, from my Bortle 8 apartment balcony

could only do 4 hours max per night thanks to my wonderful horizons from the balcony overhang

Places where I host my other images:

Instagram | Flickr

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: 110 hours 18 minutes (Camera at -15°C)

all narrowband exposures were 360" and unity gain

all broadband exposures were 30" and at half unity gain

Filter Ha Oiii Sii Red Green Blue
Panel 1 30 28 19 24 24 24
Panel 2 30 27 19 32 32 32
Panel 3 30 29 29 24 24 24
Panel 4 34 31 30 24 24 24
Panel 5 30 34 29 24 24 24
Panel 6 34 31 29 24 24 24
Panel 7 33 30 29 24 24 24
Panel 8 39 27 29 24 24 24
Panel 9 26 28 28 32 32 32
Panel 10 32 29 30 24 24 24
Panel 11 34 20 19 28 28 28
Panel 12 30 22 19 24 24 24
TOTAL: (h) 38.2 30.8 33.6 2.56 2.56 2.56

  • Darks- 30

  • Flats- 30 per filter

Capture Software:

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

PixInsight processing:

/u/Aerions_'s Heart and Fishhead pic was a bit of an inspiration for me when processing this (and imo their colors are better)

Preprocessing

  • BatchPreProcessing

  • StarAlignment

  • Blink

  • ImageIntegration per channel per panel

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

Creating the mosaic:

I had numerous other attempts to make this using microsoft ICE and mosaicbycoordinates/photometricmosaic, but they all refused to work that well. During this process I found out that the .tiff file format has a max size of around 530 megapixels

  • StarGenerator to generate a starfield of the region at the same image scale as my drizzled images

  • StarAlignment to align each drizzled stack to the synthetic starfield

despite reading all the documentation and tinkering with every setting, my blue stars channel for panel 11 refused to align properly with any of the other channels, so the stars here are a bit mismatched

  • GradientMergeMosaic to combine these aligned panels into the master stacks

  • DynamicCrop away the edges of each master

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 (thanks, /u/jimmythechicken1!)

$T * med(model) / model

  • BlurXTerminator

  • StarXterminator to completely remove stars (narrowband images will be starless processed for almost the rest of the workflow)

  • NoiseXterminator

  • HistogramTransformations to bring nonlinear

More agressive stretch for Oiii and Sii

RGB Linear:

  • ChannelCombination to combine R G and B masters into a color image

  • SpectrophotometricColorCalibration

  • HSV Repair

  • StarXterminator to make a stars only image (this stars only image to be used going forward)

  • AcrsinhStretch + HistogramTransformation to stretch nonlinear

Nonlinear:

did this over the course of a couple weeks/processing breaks so the details aren’t exact

  • PixelMath to combine stretched narrowband masters into color image

SHO --> RGB (classic Hubble Palette)

  • HistogramTransformations to adjust channel intensities

  • CurveTransformations for slight hue adjustments

  • LRGBCombination using stretched Ha as luminance

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

  • invert > SCNR > invert to remove background magentas

  • probably used BackgroundNeutralization at some point around here too

  • LocalHistogramEqualization

Two round of this: one at kernel radius 16 for the finer ‘feathery’ details and one at 200+ for larger structures

  • more curves!

  • NoiseXterminator

  • more histogramtransformation tweaks

  • DarkStructureEnhance

  • Relinearized narrowband and stars images to add in the RGB stars

“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

  • ColorSaturation

  • MLT for chrominance noise reduction

  • final round of noiseX

  • guess what baby more curves

  • one final round of DBE to remove a small red gradient in the bottom corner that made it through to the end somehow

just to please Jimmy

  • IntegerResample to 50%

  • annotation