VdB 7/9 and LDN 1355 - The Helping Hand Nebula

A cool region of sky containing (surprise) a lot of dust and reflection. LDN 1355, the helping hand nebula, is rather aptly named. It appears to sit in front of a reflection region, Van den Bergh 9. VdB 7 is visible on the right hand side of the frame.

 

- Location: Remote Observatory (Bortle 1, SQM 21.99) near Fort Davis, TX

- Total Exposure Time: 33.3 Hours

 

Equipment:

- Scope: Esprit 100ED w/ 1x Flattener

- Imaging Camera: QHY 268M

- Filters: Chroma LRGB (36mm)

- Mount: Astro Physics Mach1GTO

- Guidescope: SVBony 50mm Guidescope

- Guide camera: ASI 120mm mini

- Focuser: Moonlite Nitecrawler WR35

- Accessories: Pegasus Ultimate Powerbox v2, QHY Polemaster, Optec Alnitak Flip Flat

 

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Software:

- N.I.N.A for image acquisition, platesolving, and framing

- PHD2 for guiding

- PixInsight for processing

 

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Acquisition:

- L: 332 x 3m

- R: 113 x 3m

- G: 112 x 3m

- B: 110 x 3m

- All images at Gain 56, Offset 25 (Readout mode 1) and -5C sensor temperature

- 20 flats per filter

- Master Dark, Flat & Bias from Library

- Nights: 8/2, 8/3, 8/6, 8/7, 8/22, 8/26, 8/27, 8/29, 9/5, 9/6, 9/20, 9/21, 10/3, 10/4/22

 

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Processing:

 

- WeightedBatchPreProcessing for calibration

- Blink to remove unwanted subs

- ImageIntegration for stacking of masters

 

RGB Processing (apply to each master):

- DynamicCrop

- MureDenoise

- DynamicBackgroundExtraction

- StarAlign G and B to Red

- ChannelCombination to combine into linear RGB

- StarAlign to Lum

- HistogramTransformation x 4 to stretch

- NoiseXterminator for NR

- CurvesTransformation for saturation and hue adjustment

- ColorMask to create green chrominance mask - apply to image

- CurvesTransformation to bring down green patches

- Further unmasked CurvesTransformation to neutralize blue hue of image

 

Luminance Processing:

- DynamicCrop

- MureDenoise

- DynamicBackgroundExtraction

- StarXterminator to make starless and generate star_mask

- GeneralizedHyperbolicStretch for initial stretch to non-linear

- HistogramTransformation x3 for further strethc

- Slight NoiseXterminator for NR with Lum_mask

- CurvesTransformation for contrast

- Additional masked NoiseXterminator for NR

 

Combine Lum and RGB and further processing:

- LRGBCombination to combine Luminance and RGB

- CurvesTransformation for color balancing

- ACDNR with Luminance mask for chrominance noise reduction

- Slight CurvesTransformation for contrast

- UnsharpMask for slight sharpening

- LocalHistogramEqualization for slight detail boost

 

Add Stars back in to image:

- HistogramTransformation x3 on RGB stars - save all 3 instances of HT

- Invert -> SCNR -> invert back to remove magenta

- CurvesTransformation to remove green hue and saturate stars

- Apply saved HistogramTransformation instances to extracted Luminance stars

- LRGBCombination to combine luminance stars with RGB stars with saturation at 0.35

- CurvesTranformation on combined stars to increase blue channel

- HistogramTransformation on stars and nebula images to bring to pseudo-linear state

- PixelMath to combine stars and nebula images

- HistogramTransformation to "re-stretch" image with both nebula and stars

 

Further Processing:

- CurvesTransformation for slight contrast adjustment

- MMT to disable layer 12 for chrominance noise blotching

- Additional CurvesTransformations to color balance

- NoiseXterminator (2 rounds) with luminance mask for additional noise reduction

- Invert -> SCNR Green -> Invert to remove magenta cast

- MMT for debotch and chrominance NR using inverted luminance masks

- Final CurvesTransformation for contrast

- DynamicCrop to remove edges

- Save and export

Done