Telescope: Celestron 9.25"
Schmidt-Cassegrain at f/6.3
Focus: Prime focus
Filter: Astronomik Hydrogen Alpha
Mount: Vixen GPD with Skysensor2000
Camera: Modified Canon EOS 300D, at
Guiding: 700mm refractor guidescope,
SAC7 camera, autoguided with Guidedog software
Exposure: Total 63 mins (21 x 180s)
Date: 20th April 2005
Processing: RAW file conversion,
Offset and Dark subtraction, flat fielding, registering and stacking done in
IRIS. Only the Red channel was used. Curve stretching and a
little unsharp masking in Photoshop CS. Star ovality reduced through
making a duplicate layer and offsetting that by just one pixel using the
'darken' blending mode in Photoshop. Noise reduction in Neat Image.
New technique to reduce star ovality
worked quite well. Suggested by Erwin van der Velden. Judicious
use (settings much less aggressive than the defaults) of Neat Image was very
effective in reducing high frequency noise in the image.