VdB 152 is technically just one part at the end of the dark nebula, [and there are a number of other cataloged structures in this image](https://i.imgur.com/jPkB3oW.jpg). Captured from August 16-25, 2023. Broadband data from a Bortle 3 zone (Deerlick astronomy village), Ha from Bortle 9.
**Places where I host my other images:*
[Flickr](https://www.flickr.com/people/leftysastrophotography/) | [Instagram](https://www.instagram.com/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-290mc for guiding
* Moonlite Autofocuser
**Acquisition:** 30 hours 15 minutes (Camera at -15°C)
> BB exposures at half unity gain (76/15), Ha at unity gain (139/21)
* Ha - 102x600"
* L - 200x120"
* R - 70x120"
* G - 70x120"
* B - 68x120"
* 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 Preprocessing:**
* BatchPreProcessing
* StarAlignment
* [Blink](https://youtu.be/sJeuWZNWImE?t=40)
* ImageIntegration per channel per panel
* DrizzleIntegration (2x, Var β=1.5)
* Dynamic Crop
* DynamicBackgroundExtraction
**Luminance Linear:**
* BlurXterminator
* NoiseXterminator
* ArcsinhStretch + HistogramTransformation to stretch to nonlinear
**Ha Linear:**
> These steps largely follow the ones in [NightPhoton's advanced narrowband combination guide](https://www.nightphotons.com/guides/advanced-narrowband-combination).
* Combine Ha with Red channel (HRR palette)
* BackgroundNeutralization
* ColorCalibration
* StarXterminator to completely remove stars
* PixelMath to subtract red continuum spectrum, leaving just Ha signal
* HistogramTransformation to stretch nonlinear
* NoiseXterminator + a little concolution
* CurvesTransformation to adjust black point/contrast
> differing from the guide above, [the background was a dark gray rather than clipped to black](https://i.imgur.com/rjhndAy.png) since this is more faint structure addition than bright structure
**RGB Linear:**
* SpectrophotometricColorCalibration
* Slight SCNR Green
* HSV repair
* ArcsinhStretch + HistogramTransformation to stretch to nonlinear
> duplicate stars only was made and stretched to nonlinear using a less aggressive arcsin+HT for star addition later
**Nonlinear Processing:**
* Various curve adjustments for lightness, contrast, hue, saturation, etc (with varying lum/star masks)
* LRGBCombination using stretched L as luminance
* DeepSNR
* More curves
* PixelMath to add stretched Ha per the advanced narrowband guide above
* BlurXterminator for star reduction
> Next few steps kinda follow along with [this independent starless processing tutorial](https://www.nightphotons.com/guides/star-addition) for manually combining stars via re-linearization
* StarXterminator
* HistogramTransformation to unstretch (also applied to duplicate stars early image from earlier)
* PixelMath to combine starless + stars only images
* HT to stretch everything back to nonlinear
* [Guess what more curves](https://i.imgur.com/XEdcUeD.jpg)
* MultiscaleLinearTransform for chrominance noise reduction
* LocalHistogramEqualization (2 rounds of this at scales 68 and 384 with lum masks)
* ColorSaturation to selectively saturate reds
* Even more curves
* Resample to 70%
* Annotation
lefty7283
