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Contains:  NGC 4657, NGC 4656, NGC 4631, NGC 4627
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Whale and Crowbar Galaxies, 





    
        

            Jonathan W MacCollum
Whale and Crowbar Galaxies

Whale and Crowbar Galaxies

Technical card

Imaging telescope or lens:Orion 203/1000 f/4.9

Imaging camera:ZWO ASI071MC Pro

Mount:Celestron CGEM

Guiding telescope or lens:ZWO OAG

Guiding camera:ZWO ASI 178MM

Software:PixInsight PinInsight 1.8.5Isbeorn N.I.N.A.PHD 2

Filter:Hutech IDAS LPS D1 2"

Accessory:Skywatcher 2" Coma Corrector f/4

Resolution: 4731x3056

Dates:March 28, 2019April 2, 2019

Frames:Hutech IDAS LPS D1 2": 495x60" (gain: 90.00) -10C bin 1x1

Integration: 8.2 hours

Darks: ~60

Flats: ~30

Flat darks: ~30

Avg. Moon age: 24.67 days

Avg. Moon phase: 27.31%

Bortle Dark-Sky Scale: 4.00

Astrometry.net job: 2629230

RA center: 190.659 degrees

DEC center: 32.360 degrees

Pixel scale: 0.983 arcsec/pixel

Orientation: 1.237 degrees

Field radius: 0.769 degrees

Data source: Backyard

Description

**Whale and Crowbar Balaxies**

NGC 4631 - The Whale Galaxy (Top)
NGC 4656 - The Crowbar Galaxy (Bottom Left)
And many others

**Equipment:**

* Orion 8in f4.9 1000mm / Flocked / Mask on Turned down edge on primary

* Guiding with ZWO OAG and asi178mm camera

* ASI071mc one-shot-color cam

* Hutech IDAS LPS D1 Filter

* Celestron CGEM Mount

**Acquisition:**

* Lights: 495x60s taken across two nights in late March and Early April 2019 (8hr 15min total integration)

* Flats: 20x3s at dusk calibrated with dark flats

* Darks: 60x60s at -10C

* Bias: None

* Bortle Dark-Sky Scale: 4.00

* Pixel scale: 0.981 arcsec/pixel

* Orientation: 1* degrees

**Pre-Processing with PixInsight:**

* Calibrated and stacked using [LVA PreProcessing Steps](http://www.lightvortexastronomy.com/tutorial-pre-processing-calibrating-and-stacking-images-in-pixinsight.html)

* Integrated best 495 of 508 frames selected using a combination of Blink Subframe Selector: removing stars with bad trails and significant clouds

* Weighting:
```
15*((Stars - StarsMin) / (StarsMax - StarsMin))
+ 05*(1-(FWHM - FWHMMin) / (FWHMMax - FWHMMin))
+ 45*(1-(Eccentricity - EccentricityMin) / (EccentricityMax - EccentricityMin))
+ 35*((SNRWeight - SNRWeightMin) / (SNRWeightMax - SNRWeightMin))
+ 25
```

* No Local normalization reference

* CFA drizzled 2x and downscaled back to 1x after processing

* Crop with Dynamic Crop

* Dynamic Background Extraction

* Background Neutralization

* Photometric Color Calibration

* RGB Working space to 1,1,1

**Extract synthetic L for Deconvolution**

* Deconvolution with a Dynamic PSF L |> select 16 samples from middle of image |> Export PSF

* No De-ringing

* 5 layers of Gaussian wavelet regularization

* Use a combination of star mask generated and clone stamp created star-masks for replacing the stars and replace these stars by applying the origional non-deconvolved Luminance over-top with pixelmath

**Extract synthetic L for Noise Reduction**

* TGV Noise reduction Using a low contrast mask

* MMT Noise reduction using 8 layers and a very protective luminance mask

**Combining Sharpened L, NR L and Stretching Luminance**

* Pixel Math with luminance-based mask to apply Deconvolution image only to the non-background areas of the Noise Reduced L

* Stretch with Histogram Transformation

* Mid-stretch noise reduction with ACDNR

**RGB workflow:**

* Small Scale noise reduction using TGV Denoise

* Chrominance Noise reduction using MMT

* Stretch with Arcsin Transformation

* Curves enhance contrast and saturation

* LRGB Combination

* SCNR Red to eliminate red overcast in background

* Enhance fainter regions with multiscale median transformation

* Cleanup noise artifacts in brighter stars with star mask and light convolution

* Save as JPEG

Comments

Author

eigenVector
Jonathan W MacCollum
License: None (All rights reserved)
550
Like

Revisions

  • Final
    Whale and Crowbar Galaxies, 





    
        

            Jonathan W MacCollum
    Original
  • Whale and Crowbar Galaxies, 





    
        

            Jonathan W MacCollum
    B

B

Additional stretch and rescale

Sky plot

Sky plot

Histogram

Whale and Crowbar Galaxies, 





    
        

            Jonathan W MacCollum

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