The Rosette Nebula

The Rosette Nebula
The Rosette nebula (NGC2237-9) surrounds the open cluster NGC2244 in Monoceros. According to Burnham´s Celestial Handbook it is located at a distance of about 2600 lightyears and has a diameter of about 55 lightyears.

 © Philipp Salzgeber

Film: Kodak Multispeed / PJM-2
Telescope/Lens: Vixen 130mm (5,1″) f/5,5 Newton on a Super Polaris mount
Exposure: 20 min.
Date: 16 January 1999
Removing of Vignetting (Radial Gradient), Removing of Uneven background due to light leak (linear Gradient)


Comments:Guiding was done manually using a guidescope. This image should be regarded as a test/preliminary result, because many things were sub-optimal:

  • Manual declination corrections because of lack of declination motor
  • Film was 1 1/2 years old (stored uncooled).
  • Polar alignment was done with polar alignment scope only, no drift alignment.
  • I forgot the viewfinder magnifier and the F4 had run out of batteries, so I achieved no good focus.
  • Some light-leaks in the film can, the resulting uneven film-fog could be removed only partially.
  • Imaging with prime focus/guidescope for the first time.
  • Guidescope deliverd bad images because of misalignment of focuser and lens cell.
  • Main telescope was not collimated


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