Quote:
Originally Posted by g__day
Marc - you focus roughly on a very bright star - like Sirius - using the LCD, then via a PC hook-up I guess, take a shot, adjust and repeat until your focus is great - then away you going imaging..
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thanks for the update, but the 400D doesn't allow realtime update (ie focusing) via the LCD - it's just for settings and playback. if there is a custom setting that I have yet to discover that would be great!
I think I'm going to have to get an off-axis guider...(can you get those for Newts?)
Quote:
Originally Posted by g__day
I believe a dark frame is a shot with the lens on - so any bright bits are likely to be permanent electronic noise you can subtract out of all your real shots.
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So what you do is take a shot with the lens cap on, and subtract any values above RGB=0 from further shot in post processing, is that how it goes? I heard that you can determine the signal to noise ratio by doing this, but I thought that was it.