Ok, finally got around to processing some images acquired last Saturday, when you will recall the moon was bright (around three quarters full)
This image was taken with the ED80, Canon 300d and using my new Astronomik 1.25 inch CLS filter.(CG5 mount, autoguided, 5 inch newtonian guidescope.) 10 minute subs.
The processing was a challenge as I had to battle gradient and also vignetting..usual flat field/dark frame reduction in IRIS for some reason didn't work... had to do an unsharp mask in photoshop as well.
Finally I stacked two 10 minute images at ISO 200, and replaced the red channel in Photoshop with the red channel information from a single 10 minute exposure at ISO 1600. The wonder of it all was being able to go for such long exposure from Sydney and that too on a brightly moonlit night. Usually I get 3 minutes before white out-on a night when there is hardly any moon...suppose the filter did do its stuff as advertised. Finally noise was removed with NeatImage-default settings
Anyway IC 4685, which was sort of my target in addition to the Lagoon, has been picked up-it's the nebulosity on the right seperated from the lagoon by a dark lane. Needs a dark site and a dark night to pick up more of this nebula I'd say.
Comments welcome.
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21-July-2005, 01:56 PM
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