Hemisphere:  Northern  ·  Constellation: Andromeda (And)  ·  Contains:  Great Nebula in Andromeda  ·  M 110  ·  M 31  ·  M 32  ·  NGC 205  ·  NGC 221  ·  NGC 224  ·  The star 32And  ·  The star νAnd
M31, M32 & M110 (Astrotracer), 



    
        

            AlenK
M31, M32 & M110 (Astrotracer)
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M31, M32 & M110 (Astrotracer)

M31, M32 & M110 (Astrotracer), 



    
        

            AlenK
M31, M32 & M110 (Astrotracer)
Powered byPixInsight

M31, M32 & M110 (Astrotracer)

Technical card

Imaging telescopes or lenses: Pentax SMC Takumar 300mm f/4

Imaging cameras: Pentax K-3 II


Dates:Sept. 2, 2019

Frames: 162x20" ISO3200

Integration: 0.9 hours

Avg. Moon age: 3.55 days

Avg. Moon phase: 13.61%

Bortle Dark-Sky Scale: 4.00

Mean SQM: 20.90


Basic astrometry details

Astrometry.net job: 3258547

RA center: 0h 42' 36"

DEC center: +41° 16' 8"

Pixel scale: 8.750 arcsec/pixel

Orientation: 247.875 degrees

Field radius: 2.806 degrees


Resolution: 1920x1282

Data source: Traveller

Description

The 300mm lens was stopped down to f/5.6 for roughly half the exposures and to f/6.7 for the rest. (I was testing to see if there was a noticeable difference in star shape and/or CA. There was not.) Tracking was done internally with the camera's Astrotracer feature (no external tracker required).

The view here has been inverted compared to how the area is seen in the northern hemisphere but that is my preferred orientation since it makes the spiral nature of M31 more obvious, at least to my eyes!

Sequator was used for stacking. DBE in PixInsight LE was used for gradient reduction. Rnc-color-stretch was used for stretching. No flats, bias or dark frames were used but I aggressively dithered and used kappa-sigma clipping during stacking.

This was just a test, quickly processed. The image needs further processing, particularly better CA reduction (without, the star shapes are poor) and much more careful gradient reduction. It could also use some noise reduction; none has been applied. But I now have a total of 2.5 hours of usable frames that will be stacked for the final version, so the noise will be much less even without noise reduction.

Comments

Sky plot

Sky plot

Histogram

M31, M32 & M110 (Astrotracer), 



    
        

            AlenK