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Old 03-12-2016, 12:01 PM
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SamD (Sam)
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Join Date: Jan 2014
Location: Brisbane SW
Posts: 71
Originally Posted by ericwbenson View Post
Unless the resampling loses resolution it cannot gain SNR, otherwise it gains information for free.
However, I'm pretty sure that resampling does lose resolution, so you don't get anything for free!

For example, take a single pixel star on the original sub and resample at 0.5px in x and y. It would get smeared over surrounding pixels.

On the other hand, if the pixels in the original sub were of a uniform background, it's exactly this smearing effect that reduces the noise and improves SNR.

I think, that the lose of resolution in stacking will often explain why stack FWHM is usually less than individual sub FWHM.
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