Hemisphere:  Northern  ·  Constellation: Canes Venatici (CVn)  ·  Contains:  IC 4263  ·  IC 4277  ·  M 51  ·  NGC 5194  ·  NGC 5195  ·  Whirlpool Galaxy
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Whirlpool Galaxy, 



    
        

            jcrews
Whirlpool Galaxy
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Whirlpool Galaxy

Getting plate-solving status, please wait...
Whirlpool Galaxy, 



    
        

            jcrews
Whirlpool Galaxy
Powered byPixInsight

Whirlpool Galaxy

Equipment

Imaging Telescopes Or Lenses
Guan Sheng Optical 8" F/8 RC scope (Carbon Fiber)
Imaging Cameras
ZWO ASI2600MC Pro
Mounts
Sky-Watcher EQ6-R Pro
Accessories
TS Optics TSRCFlat2 · ZWO 5V EAF
Software
KDE KStars · Nikita Misiura DeepSNR · Pleiades Astrophoto PixInsight · pixls.us darktable
Guiding Telescopes Or Lenses
Guan Sheng Optical 8" F/8 RC scope (Carbon Fiber)
Guiding Cameras
ZWO ASI290MM Mini

Acquisition details

Dates:
April 27, 2023 ·  April 29, 2023
Frames:
40x180" (2h) (gain: 100.00) f/8.1 -10°C bin 1x1
45x240" (3h) (gain: 100.00) f/8.1 -10°C bin 1x1
Integration:
5h
Darks:
30
Flats:
20
Flat darks:
20
Avg. Moon age:
7.93 days
Avg. Moon phase:
55.66%
Bortle Dark-Sky Scale:
5.00
Mean FWHM:
3.00
Temperature:
13.00

Basic astrometry details

Astrometry.net job: 7630030

RA center: 13h29m53s.10

DEC center: +47°1149

Pixel scale: 0.951 arcsec/pixel

Orientation: 8.367 degrees

Field radius: 0.487 degrees

Resolution: 3066x2042

File size: 1.4 MB

Locations: Round Rock, Round Rock, TX, United States

Data source: Backyard

Description

A few more processing steps were added to this color image set:

Preprocessing:
Images were calibrated as usual and stacked with 1x1 square Bayer drizzle. This image was then spectrographically calibrated with GAIA Data Release 3 data and any gradient was removed with DynamicBackgroundExtraction.

Postprocessing:
First, L (luminance) was synthesized from RGB and given a minimal TGVDenoise. This image was split in two to generate a target and object mask.

Object mask: MTF clip lower 50% of signal (linear histogram peak at 0%). Midtones adjusted to amplify strong signal areas. This protects the background from deconvolution.

Target: PSFImage script used to model Point Spread Function for deconvolution. StarMask process with binarize, aggregate, low noise threshold to select stars into a de-ringing support image. This was further convoluted (sigma=4) to soften the edges.

Linear target deconvoluted with 70+10 iterations (two operations) using PSF model and local de-ringing support. This process uses the PSF model to estimate and invert the convolution (blurring) process caused by the atmosphere, sharpening the image slightly. Without local de-ringing, bright stars would appear as though circles were drawn around them.

RGB stretched with generalized hyperbolic transform sequence (RGB/K stretching with a single saturation enhancement), and R/G/B extracted.

The L channel was finally stretched with a GHT to enhance structural contrast, LinearFit to the G channel.
LRGB combination at 50/50 produced the output image.

Comments

Revisions

  • Final
    Whirlpool Galaxy, 



    
        

            jcrews
    Original
  • Whirlpool Galaxy, 



    
        

            jcrews
    B

B

Title: Annotated

Uploaded: ...

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Sky plot

Histogram

Whirlpool Galaxy, 



    
        

            jcrews