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 117 mins (39 x 180s)
Date: 16th May 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 half a pixel using the
'darken' blending mode in Photoshop. Noise reduction in Neat Image.
A humid night in between days of rain - 26 deg C, 95-99%
windless. Transparency was very good. Stayed up
till 5 am for this! Guiding worked very well indeed - only had to discard 1
out of 40 frames taken. Total exposure of nearly 2 hrs.