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Messier 31 (OSC), 



    
        

            Linda
Getting plate-solving status, please wait...
Messier 31 (OSC), 



    
        

            Linda

Acquisition details

Dates:
Dec. 18, 2018
Frames:
621×15(2h 35′ 15″) (gain: 120.00) 0°C
Integration:
2h 35′ 15″
Darks:
100
Flats:
100
Bias:
500
Avg. Moon age:
10.23 days
Avg. Moon phase:
78.49%

Basic astrometry details

Astrometry.net job: 2512444

Resolution: 3522x2558

File size: 7.0 MB

Locations: Home, Broadlands, VA, United States

Data source: Backyard

Description

I've been having tracking issues with my mount that I'm still trying to track down so I thought I'd try an experiment in short exposure photography. This was 621 frames with 15 second exposures at gain 120 on an ASI294MC Pro.

Overall it worked better than I expected. It looks like my focus creeped a bit while I was sleeping (really need to get some automated focusing going) and the background looked a bit blotchy after running DBE but I was able to keep it under control for the most part.

I tried to be fairly gentle in the processing:

DBE

PCC

Luminance and chrominance noise reduction with MLT

iterative HT stretching

saturation boost with Curves (using a mask to not saturate the background)

mild LocalHistogramEquilization for some contrast enhancement

I really didn't want to do this with a nearly full moon in the sky but between a crazy work schedule and a record breaking year for rain there haven't been many opportunities in the last couple of months. I figured the experiment had value even if I didn't get anything useful from it. As it turned out, it was better than expected. Going to try using slightly longer exposures or higher gain or both to see if there is a sweet spot.

Constructive criticism always welcome.

Comments

Revisions

  • Messier 31 (OSC), 



    
        

            Linda
    Original
  • Messier 31 (OSC), 



    
        

            Linda
    B
  • Messier 31 (OSC), 



    
        

            Linda
    C
  • Messier 31 (OSC), 



    
        

            Linda
    D
  • Messier 31 (OSC), 



    
        

            Linda
    E
  • Final
    Messier 31 (OSC), 



    
        

            Linda
    F

B

Description: I ran PI's Dark Structure Enhance using default settings to help bring out the dust lanes a bit. Seems to help a bit.

Uploaded: ...

C

Description: This is a reprocessing that eliminates the background splotchiness and (mostly) tames the complex gradients.

Uploaded: ...

D

Description: A bit of cropping to remove some gradient edges.

Uploaded: ...

E

Description: A hopefully final revision. Ran the dark structure enhance script and shifted the color balance slightly warmer. It was coming across a bit harsh in the previous revision.

Uploaded: ...

F

Description: With the weather not cooperating, I decided to revisit this and see if I could do better. My goals were to minimize the background blotchiness and maximize detail in the galaxy. I may have pushed it a bit too far. What does everyone think?

Uploaded: ...

Histogram

Messier 31 (OSC), 



    
        

            Linda