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Old 08-12-2008, 12:55 PM
TrevorW
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Noisey CCD DSLR

Ok the attached are two frames taken are 1hr apart on the 5/12/08 of M45

each is a 2min exposure setting ISO800

I've been having problems of late getting images to come our OK even after applying flats and darks still a lot of noise i nthe images

How noisey are these in comparison to others who take 2 minutes exposure.

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Old 08-12-2008, 01:05 PM
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That is about what I am getting (with Canon 400D)
You also have a lot of LP, and some dust on your sensor...
However, stacking should smooth the noise out.
With LP, you have to process it out.

I hope you do not mind, I did a very rough processing, see attached picture.
Smaller pic is a crop from one of my exposures, it is 60 sec but with ISO1600, so sort of the same thing...
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Last edited by bojan; 08-12-2008 at 01:51 PM.
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Old 09-12-2008, 08:05 AM
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The noise will increase with the ambient temperature. Temps of 15 or greater will show much more noise than those taken at 10 degrees or less.
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Old 09-12-2008, 12:49 PM
TrevorW
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Average temp of these nights was between 15 and 20 I was taking images between 9 and 11 pm so maybe I should wait until after midnight when ambient temp should drop significantly
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Old 09-12-2008, 05:12 PM
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Trevor,
What you are talking about (pink background) looks like LP to me. And it may change with time since the object is moving.
Noise will be visible if you take darks..
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Old 09-12-2008, 05:38 PM
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I've seen similar effects with long exposures on Kodak and Fuji Colour print film on printing - that's mostly light pollution in my view.

Get a Deep Sky, UHC or LPF filter.
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