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Contains:  M 101, NGC 5457
Getting plate-solving status, please wait...
Messier 101 revisited, 





    
        

            Daniel.P
Messier 101 revisited

Messier 101 revisited

Technical card

Resolution: 2906x1994

Dates:May 9, 2015April 30, 2019May 4, 2019May 29, 2019

Frames:
71x600"
AstroDon 5nm Ha filter: 4x600" (gain: 139.00) -21C bin 1x1
AstroDon 5nm Ha filter: 7x600" -18C bin 1x1
ZWO new L: 15x120" (gain: 139.00) -21C bin 1x1
ZWO new L: 36x120" -18C bin 1x1

Integration: 15.4 hours

Avg. Moon age: 24.80 days

Avg. Moon phase: 28.61%

Astrometry.net job: 2745125

RA center: 210.810 degrees

DEC center: 54.346 degrees

Pixel scale: 0.759 arcsec/pixel

Orientation: 262.072 degrees

Field radius: 0.371 degrees

Locations: Duc, Prayssas, Lot et Garonne, France

Data source: Backyard

Description

I have taken some Lum and Ha exposure with my APO and ASI1600mm set-up and combine them to 2015 single shot color exposure from 2105 (71x600" -15C bin 1x1 ).

The process was as follows in PI:
- I took the 2015 linear image (after integration and DBE)
- I Extract the CIE L*a*b channels

- I performed the usual preprocessing for the 2019 data to produce integrated linear image in L and Ha channels

- I did a weigheted integration of the L channel from 2015 data and Lum channel from the 2019 data using integration in PI
- I recombined channels in a collor image

- when NL for both the color image and the Ha image
- I slip the color image in RGB channels
- I add (with some weighting) the R and Ha channels
- I recombined the resulting RGB channels
- Green removal using SCNR
- Color Saturation with mask to protect background
- TGV noise removal
- Local Histogram Equalization

Final adjustement on iMac Photos

The 2 other versions are :
- D : did a masked strech instead of a pure Histo Transform
- E : using the full field of 2019 image, but not all the image is colored

Comments

Author

Daniel.P
Daniel.P
License: None (All rights reserved)
1692
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Revisions

  • Final
    Messier 101 revisited, 





    
        

            Daniel.P
    Original
  • Messier 101 revisited, 





    
        

            Daniel.P
    D
  • Messier 101 revisited, 





    
        

            Daniel.P
    E

D

LHEq

E

Full Frame - only partialy colored

Sky plot

Sky plot

Histogram

Messier 101 revisited, 





    
        

            Daniel.P