Markarian's Chain

Second completed image of 2021 and the first complete one from my local astronomy club's dark site, an hour and a half outside of Houston. We finally had the first clear new moon weekend of the year, and myself and many others in the club decided we had to take advantage of it. It was a beautiful night with no clouds and the dew kept at bay. Had to image something unique for galaxy season and I settled on Markarian's Chain in Virgo. I framed to to get as many individual galaxies as I could in one shot.

 

- Location: Houston Astronomical Society's Dark Site (Bortle 4)

- Total Integration Time: 6.65 Hours

 

Equipment:

- Scope: TS107 w/ 0.79x Reducer

- Imaging Camera: QHY 268M

- Filters: Chroma LRGB 36mm

- Mount: Skywatcher EQ6-R Pro

- Guidescope: SVBony 50mm Guidescope

- Guide camera: QHY5L-ii mono

 

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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: 61 x 180"

- R: 25 x 180"

- G: 24 x 180"

- B: 24 x 180"

- All images at Gain 56, Offset 25 (Readout mode 1) and 0C sensor temperature

- 20 flats per filter

- Master Dark from library

- Master Bias from Library

- Nights: 4/10/21

 

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Processing:

 

- BatchPreProcessing to generate calibrated files

- SubFrameSelector to weight files

- ImageIntegration, DrizzleIntegration of masters

 

Luminance Processing:

- DynamicCrop

- DynamicBackgroundExtraction (x2 - subtraction and division)

- Deconvolution

- TGV Denoise

- MMT Blotch fix for TGV (MMT NR on wavelet layers 5/6/7 with inverted Luminance Mask)

- MMT Denoise on wavelet layers 1/2/3/4/8 (with MMT Mask)

- MaskedStretch for initial stretch with no clipping

- HistogramTransformation for slight further stretch

 

RGB Processing (to each master):

- DynamicCrop

- DynamicBackgroundExtraction

- StarAlignment of G and B to R

- ChannelCombination to combine to color image

- PhotometricColorCalibration

- MaskedStretch to bring to non-linear

- CurvesTransformation to bump saturation and contrast slightly

- HistogramTransformation to stretch a bit more to match RGB peak level to Luminance

 

Combine Luminance and RGB:

- StarAlign RGB to Luminance

- LRGBCombination with chrominance noise reduction enabled and saturation slider reduced to 0.2

 

Further Processing:

- PreviewAggregator script to combine 4 background previews

- BackgroundNeutralization to neutralize BG of image

- RangeSelection to make mask and CurvesTransformation to increase galaxy saturation

- MMT Chrominance Noise Reduction on galaxies using same RangeMask

- Starnet/Binarize/Convolution to create StarMask from Luminance

- RangeMask + LocalHistogramEqualization to slightly enhance galaxy details

- StarMask + MorphologicalTransformation for slight star reduction

- Combine RangeMask and StarMask via PixelMath and apply and invert

- HistogramTransformation to darken background

- Invert mask to normal and CurvesTransformation for final saturation boost

- FastRotation to Flip 180

- DynamicCrop to crop edge artifacts

- IntegerResample to downsample

- Save and Export

Done