Quote:
Originally Posted by vanwonky
Lets say I take a 60sec/800 iso image of M42. Why not just use that same image 20 times in your stacking program? Is it not the same data if I take it once or 20 times?
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Using the same sub 20 times will not do anything to the image, the noise in the image is the same and so the softwares stacking method has nothing different to work with.
Quote:
Originally Posted by vanwonky
Admittedly I am yet to understand what 'magic' goes on with the software when stacking like images so I might be missing something quite basic here. Is it just noise reduction that is the benefit?
Cheers
Dave
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Yes noise reduction is the benefit, the software exploits the fact that signal is not random and noise is. As a simple example think of one pixel that is bright in a picture, if this due to signal then it would be in any subsequent frames and the average of those pixels would be a bright pixel. Think now that the bright pixel was due to noise, it may not be in subsequent frames (because it is random) so a bright pixel will be averaged with other sub frames that are dim, this will result in the pixel looking dimmer. And the more subframes you take that dont contain the bright pixel the dimmer it would look.
Obviously this is very simplistic but it should give you an idea of whats going on.