Influences on the image quality:  Experience in image processing

Example: M63
First image processing in 2001
(experience 1,5 Jahre)

Software: AstroArt V1.5: dark frame correction,  VBE-correction, anti-aliasing, LRGB-Extraction using AA-Plugin, 60% anti-aliasing, 10% anti-saturation,
RGB: Gauss-Blur (2) and FFT-deep pass filter, automatic histogram -stretch
L: addition of frames, flat field correction,  adapt. unsharp mask (3.5/1.5), extreme log-histogram stretch

 

problems:

  • background  inhomogeneous and  noisy

  • large stars 

  • stars without color

  • hard boarder between  galaxy and background

  • centre of galaxy burned out

 

Bildbearbeitung Mai 2001
Second attempt in2005
(Erfahrung 5 Jahre) 

Software: AstroArt V3, AIP, Picture Window Pro.
dark frame correction,  artificial flat field correction, LRGB-extraction using Mike's-Plugin,
RGB: Gauss-blurr (1.5), color balance using white star method,
L: Richardson-Lucy-deconvolution (AIP), non-linear histogram stretch, lightning of galaxy using mask, adaptive unsharp mask (AA), hotpix eliminated, border between galaxy and background smoothened using a light Gauss-blurr .

 

Bildbearbeitung Februar 2005

Data:

  • Telescope: Celestron C8 on Vixen GP

  • Celestron F6.3 focal  reducer

  • IR-filter

  • Camera: Starlight MX5C ("One shot color")

  • Guiding: none

  • Exposure: 60x1min

 

 

Conclusions:

  • The 12 bit- dynamic of the MX5C often needs the addition of the frames instead of the (in principle more advantageous) averaging. Averaging in such cases results in less gray scales and less smooth intensity steps.
  • The artifical flat field reduces effectively the nonlinear background intensity.
  • The plugin created by Mike Smith improves the LRGB-extraction from the raw data.
  • Often a user-defined RGB-scaling results in a more accurate color balance combined to the automatic stretch of the histogram done by AA.
  • The Richardson Lucy deconvolution provided by the AIP software is very effective in reducing star diameters and enhancing fine details.
  • The adaptive unsharp mask sometimes works better on galaxies.
  • Short single exposures clearly limit the capabilities of mage processing.