vdB 141 - The Ghost Nebula

I totally didn't procrastinate processing this thing, and it's just *pure coincidence* that I finally took a stab at it in October...

 

In hindsight, this really could've used another night of data (particularly the L), but I only had one clear night at the dark site. I was just happy to get out of the light pollution and shoot a dark nebula for once! Captured on August 17th, 2025 from a bortle 3 zone (deerlick astronomy village).

 

**Places where I host my other images:**

 

[Flickr](www.flickr.com/people/leftysastrophotography/) | [Pixelfed](pixelfed.art/lefty)

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**[Equipment:](i.imgur.com/BsmkAmF.jpeg)**

 

* 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:** 7 hours 21 minutes (Camera at -15°C), half unity gain

 

* L - 56x180"

 

* R - 30x180"

 

* G - 30x180"

 

* B - 31x180"

 

* Darks- 30

 

* Flats- 30 per filter

 

**Capture Software:**

 

* Captured using [N.I.N.A.](nighttime-imaging.eu/) and PHD2 for guiding and dithering.

 

**PixInsight Preprocessing:**

 

* BatchPreProcessing

 

* StarAlignment

 

* Blink

 

* ImageIntegration per channel

 

* DrizzleIntegration (2x, Var β=1.5)

 

> For the L channel I did 3 stacks each with 1/3rd of the data, then combined them to an RGB image (was still grayscale) to use deepSNR noise reduction. after this it was properly converted to mono

 

* Dynamic Crop

 

* MultiscaleGradientCorrection

 

> First time trying out the [MARS thing in pixinsight](pixinsight.com/mars/). It seems to work very well

 

**Luminance Linear:**

 

* BlurXterminator

 

* Stars removed with starx

 

* ArcsinhStretch + HistogramTransformation to stretch nonlinear

 

**RGB Linear:**

 

* ChannelCombination to combine monochrome R G and B images in to single color image

 

* MultiscaleGradient Correction

 

* SpectrophotometricColorCalibration

 

* BlurXterminator (correct stars only)

 

* HSV Repair

 

* Extracted stars with starXterminator, to be used later for [independent starless processing](www.nightphotons.com/guides/star-addition/)

 

* ArcsinhStretch + HistogramTransformation to stretch nonlinear

 

* Slight saturation curve boost

 

** Stars only processing:**

 

* ArcsinhStretch + HistogramTransformation to stretch nonlinear

 

* Slight SCNR to remove greens and magentas

 

* Curves to boost saturation

 

 

**Nonlinear Processing:**

 

* LRGBCombination to combine stretched RGB and L images

 

* DeepSNR Noise reduction

 

* Several rounds of curve adjustments for lightness, contrast, saturation, color balance, with various masks

 

* LocalHistogramEqualization

 

* More curves

 

* Pixelmath to add in the stretched RGB stars only 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](www.nightphotons.com/guides/star-addition))

 

> mtf(.005,

 

> mtf(.995,Stars)+

 

> mtf(.995,Starless))

 

* BlurX to sharpen the stars a little

 

* Even more curves

 

* Slight SCNR

 

* Resample to 70%

 

* Tighter crop in on just the nebula

 

* Annotation

Done