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Abell 21 (SH2-274) - The Medusa Nebula (Bicolor)

Technical card

Resolution: 2307x2365

Dates:Feb. 24, 2019Feb. 25, 2019Feb. 26, 2019Feb. 27, 2019

Astronomik H-Alpha 6nm CCD: 45x900" -20C bin 1x1
Astronomik OIII 6nm CCD: 36x900" -20C bin 1x1

Integration: 20.2 hours

Darks: ~50

Flats: ~10

Bias: ~200

Avg. Moon age: 21.64 days

Avg. Moon phase: 55.22%

Bortle Dark-Sky Scale: 4.00 job: 2942166

RA center: 112.242 degrees

DEC center: 13.328 degrees

Pixel scale: 0.925 arcsec/pixel

Orientation: 358.491 degrees

Field radius: 0.424 degrees

Locations: Home, Bergisches Land, Germany

Data source: Backyard


Bad weather here, so I decided to rework on my data of Abell 21. :-) Even if I only gathered bicolor data (H-Alpha and OIII), I wanted to get that typical impression of a Hubble pallet. I think it's been worth it. :-)

Also known as Abell 21 and SH2-274, the Medusa Nebula is an old planetary nebula some 1500 light-years away in the constellation Gemini.



Frank Breslawski
License: Attribution-NonCommercial-ShareAlike Creative Commons

Sky plot

Sky plot


Abell 21 (SH2-274) - The Medusa Nebula (Bicolor), 


            Frank Breslawski