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yeah, the exit pupil part of the equation has got me wondering as well...I'm kinda thinking out loud here paddy, so sorry if I'm paraphrasing you...
going back to the 24mm Pan vs 17mm Tele figures
24mm Panoptic - field stop=27mm; TFOV=1.29º; exit pupil=4mm
17mm Nagler - field stop=24.3mm; TFOV=1.16º; exit pupil 2.8mm
For the sake of trying to figure out how exit pupil affects what the object being observed actually looks like through the eyepiece, I'm going to assume the TFOV of both eyepieces is the same....
So, with this assumption in mind, what we are dealing with is the same amount of information (light) gathered by each eyepiece, are we not? If so, then if that amount of information is spread over a larger area, would it not be easier to see detail? Does this also mean, however, that any background 'noise' would also be more obvious?
So, does the larger exit pupil eyepiece give a more detailed view of a given object, with less contrast, than an eyepiece with a smaller exit pupil, given the same AFOV between the two?
I know this doesn't take into account the way the eye behaves...all I'm trying to do here is understand how exit pupil works....there are probably a multitude of other factors I'm not even aware of that enter the equation...
Any help/insight greatly appreciated....
it also makes me wonder if, rather than thinking of magnification, I'm better off choosing eyepieces based on TFOV/exit pupil....perhaps try to match TFOV while having a selection of various exit pupil sizes....
I got my TFOV figure from a post by gargoyle_steve:
TFOV = (180/Pi)*field stop / Scope focal length.
180/Pi converts the calculation from radians to degrees - approx 57.296
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