So technically 32 Cygni is just the bright star in the pic, and the rest of it is just hydrogen gas floating around in space. The constellation Cygnus has a ton of this hydrogen-alpha gas floating around, and I kinda just pointed at a semi-random spot in the constellation to get a pic. Although this was taken with an Ha filter, the stars are true color RGB, and I mapped the Ha channel to red so it closely resembles the actual color of hydrogen-alpha. Also for those curious here is a starless version that better shows the faint nebulosity/structures. Also pls ignore the crunchiness around 32 Cyg itself, it’s an artifact of my camera’s microlensing + the star removal program I use. Captured over like a dozen nights in December 2024 from a bortle 9 zone.
Acquisition: 29 hours 18 minutes (Camera at -15°C), unity gain
Ha - 161x600"
R - 51x60"
G - 59x60"
B - 48x60"
Darks- 30
Flats- 30 per filter
Capture Software:
Captured using N.I.N.A. and PHD2 for guiding and dithering.
PixInsight Preprocessing:
BatchPreProcessing
StarAlignment
Blink
ImageIntegration per channel
DrizzleIntegration (2x, Var β=1.5)
Dynamic Crop
DynamicBackgroundExtraction
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
Narrowband Linear:
Blur and NoiseXTerminator
StarXterminator to completely remove stars from each the image
HistogramTransformation to stretch nonlinear (calling this the Ha image now)
Broadband/RGB linear:
ChannelCombination to make color image from R G and B stacks
StarX (correct only)
SpectrophotometricColorCalibration
(duplicated image at this point, to be used for stars only processing later)
StarX to completely remove stars (at this point it’s just background, with a little bit of signal in the R channel)
Blended unstretched Ha image into the red (and a little bit of the blue channel) with this pixelmath:
R = $T+B*(Ha- med(Ha))
G = $T
B = $T+B*0.2*(Ha- med(Ha))
honestly can’t remember what I used for the B constant, but the default is 2 in my pixelmath ¯\_(ツ)_/¯
HistogramTransformation to stretch nonlinear (calling this the Starless image now)
Stars only processing:
HSV repair to fix blown out star cores
StarXterminator to generate an image containing only the stars (without any background)
ArcsinhStretch + Histogramtransformation to stretch nonlinear (Calling this the Stars image now)
Nonlinear:
LRGBCombination to add the stretched Ha image to the stretched Starless image as a luminance layer
NoiseXterminator
Background neutralization
Several curve transformations to adjust lightness, contrast, saturation, color balance, etc
LocalHistogramEqualization
Another round of noiseX
Pixelmath to add in the stretched RGB Stars image from earlier
This basically re-linearizes the two images, adds them together, and then stretches them back to before. More info on it here)
mtf(.005,
mtf(.995,Stars)+
mtf(.995,Starless))
few more curve adjustments
FastRotation 180 degrees (pic was originally upside down)
So technically 32 Cygni is just the bright star in the pic, and the rest of it is just hydrogen gas floating around in space. The constellation Cygnus has a ton of this hydrogen-alpha gas floating around, and I kinda just pointed at a semi-random spot in the constellation to get a pic. Although this was taken with an Ha filter, the stars are true color RGB, and I mapped the Ha channel to red so it closely resembles the actual color of hydrogen-alpha. Also for those curious here is a starless version that better shows the faint nebulosity/structures. Also pls ignore the crunchiness around 32 Cyg itself, it’s an artifact of my camera’s microlensing + the star removal program I use. Captured over like a dozen nights in December 2024 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-290mc for guiding
Moonlite Autofocuser
Acquisition: 29 hours 18 minutes (Camera at -15°C), unity gain
Ha - 161x600"
R - 51x60"
G - 59x60"
B - 48x60"
Darks- 30
Flats- 30 per filter
Capture Software:
PixInsight Preprocessing:
BatchPreProcessing
StarAlignment
Blink
ImageIntegration per channel
DrizzleIntegration (2x, Var β=1.5)
Dynamic Crop
DynamicBackgroundExtraction
Narrowband Linear:
Blur and NoiseXTerminator
StarXterminator to completely remove stars from each the image
HistogramTransformation to stretch nonlinear (calling this the Ha image now)
Broadband/RGB linear:
ChannelCombination to make color image from R G and B stacks
StarX (correct only)
SpectrophotometricColorCalibration
(duplicated image at this point, to be used for stars only processing later)
StarX to completely remove stars (at this point it’s just background, with a little bit of signal in the R channel)
Blended unstretched Ha image into the red (and a little bit of the blue channel) with this pixelmath:
HistogramTransformation to stretch nonlinear (calling this the Starless image now)
Stars only processing:
HSV repair to fix blown out star cores
StarXterminator to generate an image containing only the stars (without any background)
ArcsinhStretch + Histogramtransformation to stretch nonlinear (Calling this the Stars image now)
Nonlinear:
LRGBCombination to add the stretched Ha image to the stretched Starless image as a luminance layer
NoiseXterminator
Background neutralization
Several curve transformations to adjust lightness, contrast, saturation, color balance, etc
LocalHistogramEqualization
Another round of noiseX
Pixelmath to add in the stretched RGB Stars image from earlier
few more curve adjustments
FastRotation 180 degrees (pic was originally upside down)
DynamicCrop again (just a little bit)
Resample to 60%
Annotation