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Contains:  NGC 5485, NGC 5474, NGC 5473, M 101, NGC 5457
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M101 - Fast exposures with Samyang 135, 





    
        

            netspoon
M101 - Fast exposures with Samyang 135

M101 - Fast exposures with Samyang 135

Technical card

Resolution: 3912x2928

Dates:April 12, 2019

Frames:Baader UV/IR Cut: 1155x5" (gain: 300.00) 21C

Integration: 1.6 hours

Darks: ~450

Avg. Moon age: 7.08 days

Avg. Moon phase: 46.77%

Bortle Dark-Sky Scale: 6.00

Astrometry.net job: 2707892

RA center: 211.104 degrees

DEC center: 54.304 degrees

Pixel scale: 1.991 arcsec/pixel

Orientation: 359.635 degrees

Field radius: 1.351 degrees

Locations: Backyard, Saint-Orens de Gameville, France

Data source: Backyard

Description

I wanted to try the fast exposures approach.

- gain 300 / offset 140 to get the min read noise

- 5 seconds sub. 75 % of the best subs have been kept (stacked with DeepSkyStacker).
Image C shows one 5'' sub with background extraction and stretched.

- despite of heavy light pollution i used the UV-IR cut instead of the CLS because i wanted the maximum possible light. Lens opened at f/2.

- no guiding

- less polluted location + cooling the camera would improve the SNR that is weak

- the result can be compared to B : 30'' subs, gain 76 (but with CLS and flats for this one)

- Now stack in PI and reprocessed

Comments

Author

netspoon
netspoon
License: None (All rights reserved)
1341
Like

Revisions

  • M101 - Fast exposures with Samyang 135, 





    
        

            netspoon
    Original
  • M101 - Fast exposures with Samyang 135, 





    
        

            netspoon
    B
  • M101 - Fast exposures with Samyang 135, 





    
        

            netspoon
    C
  • Final
    M101 - Fast exposures with Samyang 135, 





    
        

            netspoon
    D

B

30'' subs. With flats.

C

One 5'' sub. With background extraction and stretched

D

Drizzle, reprocessed

Sky plot

Sky plot

Histogram

M101 - Fast exposures with Samyang 135, 





    
        

            netspoon

In these public groups

Samyang 135 f/2