Resolution of observation telescopes?

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Summary:
Observation telescope stats.
I was wondering how the resolution is of a observatory station and compare that to its field of view? Higher rez with larger field or higher rez with more narrow field but much more scanning across the sky to create full images?
 

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  • #2
Tom.G
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sophiecentaur
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Summary:: Observation telescope stats.

I was wondering how the resolution is of a observatory station and compare that to its field of view? Higher rez with larger field or higher rez with more narrow field but much more scanning across the sky to create full images?
I think your question could be based on a false dichotomy. You are not really comparing like with like. Resolution is not the only relevant factor in astronomy. Pushing the system to see (and resolve) as many stars as possible involves the good old Signal To Noise Ratio. Your two scenarios are including the implication that you want to scan a particular region of sky and not just to resolve two distant, faint objects. The diffraction limit is set by the diameter of the objective lens (at least, that's a major factor). If you use a long focus / narrow angle then your sensor can have bigger elements and, therefore more sensitivity to a given elemental angle of view.

But if you want to scan a wide field, either the focal length of the objective your sensor would need to be shorter and, to make use of this wider field, the element area would need to be less in order still to resolve the two faint objects and have room for many more on the image.

Otoh, you could stick with the original scope and scan it around. Apart from practical details, the longer time to get your big image by scanning the scope around would be very much of the same order as the extra exposure time you'd need to get high enough signals from your finer pitch sensor elements behind a wider angle lens.

That's probably a gross oversimplification but it's got to be based on the total Energy flux from each area of space onto a sensor.
 

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