Image info
Telescope: Orion 80ED apochromatic
refractor at f/7.5
Focus: Prime focus
Filter: Astronomik Hydrogen Alpha
13nm FWHM, Astronomik RGB.
Mount: Vixen GPD with Skysensor2000
Camera: Artemis 285 CCD camera
Guiding: 700mm refractor guidescope,
SAC7 camera, autoguided with Guidedog software
Exposure: Total 130 mins (26 x 300s)
H-alpha, 72, 39, 9 mins R,G,B.
Date: 24th June & 1st July 2006
Processing: For all frames, offset and flat
fielding, registering and stacking done in IRIS. No dark frames.
RGB combination is first done in IRIS, and star colours are calibrated with
a G2V star. LRGB compositing, curve stretching, Levels, Smart Sharpen in Photoshop CS2.
LRGB compositing is through the process of
"Luminance
Corrected LRGB" as described by Steve Cannistra. The R component
of the RGB is first mixed with H-alpha in Photoshop and then recombined into
a new RGB. The Luminance layer starts as pure H-alpha but with a
correction layer whose opacity is reduced in subsequent iterations.
Pls see the link above for details.
Noise reduction in Neat Image.
The stars in the luminance layer were
slightly trailed (therefore slightly oval), so this was corrected in
Photoshop.
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