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Old 12-03-2017, 01:35 PM
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Slawomir (Suavi)
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Join Date: Sep 2014
Location: North Queensland
Posts: 3,240
Optimal sampling

Dear fellow astrophotographers.

Perhaps this topic has been discussed over and over, but I thought it would not hurt to have a look at optimal sampling yet again.

If we would like to get the most out of a telescopic imaging system in terms of resolution and real estate, perhaps slight under-sampling combined with dithering and drizzle integration might yield most optimal results.

Slight under-sampling usually means we can use a smaller telescope that is less demanding on the mount and is cheaper than a larger telescope of the same built quality. It also means we cover a somehow larger field in our images as opposed to imaging at less arc-seconds per pixel with the same camera. Drizzle integration when applied properly recovers some detail thus increases resolution in the final image.

This was my exact thinking when I recently bought a new telescope. For good or bad, I resisted a very strong temptation to get a larger telescope. My new imaging system will sample outer space at 1.21 arc-seconds per pixel. Drizzle x2 will increase the scale to about 0.6 arcseconds per pixel, but more realistically I feel that the true detail in final images will be probably comparable to what I would get when imaging at about 1 arc-second per pixel (maybe less), while the filed of view captured in final images will be larger.

So in theory, if I permanently incorporate drizzle integration in my data processing, I should be getting seeing-limited detail as long as I will be shooting from a near coastal location in Australia. Of course I have not considered light pollution, pixel well depth etc, but that I feel is a different story.

Any thoughts, and also pointing errors in my reasoning, will be highly appreciated.

Suavi
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