LBN 468 and Dust in Cepheus

LBN 468 is a dark nebula located in the constellation Cepheus. From my observations, there are way more images of its next door neighbor, the Iris Nebula, and thus I decided to image this guy. There is so much dust in this region that even doing background extraction took very careful placement of points.

 

A curious object, Gyulbudaghian's Nebula can be seen at the left hand tip of the central dust. This nebula, first discovered in 1977, has been changing in intensity constantly since. It lies at the heart of Herbig Haro 215. Jets of dust can be seen streaming away from the star at right angles but the nebulosity looks very different than images captured as recently as 4 years ago, lightning quick in astronomical timescales.

 

This image is a 2-panel mosaic taken over 14 nights, with approximately 20 hours of exposure time per panel.

 

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

- Total Exposure Time: 40.95 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 (Total between both panels):

- L: 400 x 3m

- R: 146 x 3m

- G: 138 x 3m

- B: 135 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: 7/9, 7/10, 7/16, 7/17, 7/19-7/24, 7/28-7/31/22

 

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Processing:

 

- BatchPreprocessing for calibration

- Blink to remove subs with clouds

- ImageIntegration to integrate both panels for each master

 

Combine panels for each master:

- DynamicCrop to crop edges

- DynamicBackgroundExtraction on each panel per filter

- Save

- ImageSolver script to platesolve each panel

- MosaicbyCoordinates script to create templates for each master

- TrimMosaic script 1px in all 4 edges

- PhotometricMosaic to stitch all panels to create LRGB 2-panel masters

 

RGB Processing (apply to individual masters):

- FastRotation 90 degrees counterclockwise

- DynamicCrop to remove mosaic edges

- DynamicBackgroundExtraction

- NoiseXterminator for linear NR

- StarAlign Green and Blue masters to Red

 

Combine RGB and futher processing:

- ChannelCombination to combine into RGB color image

- DynamicBackgroundExtraction x2 to remove residual color gradients

- BackgroundNeutralization

- Arcsinhstretch x2 for initial RGB stretch

- HistogramTransformation for further stretch

- SCNR green to remove green tint

- Invert -> SCNR Green at 0.5 -> invert back to remove magenta

 

Luminance Processing:

- DynamicCrop to remove mosaic edges

- DynamicBackgroundExtraction

- NoiseXterminator for linear NR

- GeneralizedHyperbolicStretch for intial stretch

- HistogramTransformation x2 for further stretch

- CurvesTransformation for contrast

- NoiseXterminator to target low signal area NR

 

Combine Luminance and RGB and further processing:

- StarAlign RGB to Luminance

- LRGBCombination to combine RGB and Luminance w/ Chrominance NR enabled

- CurvesTransformation with star_mask for contrast and saturation

- Extract Luminance and apply inverted Lum as mask, NoiseXterminator for slight noise reduction

- MorphologicalTransformation with star_mask to slightly reduce stars

- Duplicate and run slight 'c' curve to slightly balance color

- PixelMath to blend 50-50 with original

- Save and Export

Done