I know I will most likely be hammered for this but......
I don't entirely buy the "too big an exit pupil wastes light" theory !
I understand the concept that too big an exit pupil EP...causes light to fall on the iris and not into the pupil. Thereby wasting light
and / or stopping down the view.
Here is my counter 'theory'.
1) I believe the retina is many many times as wide as our pupils - in all directions. ( Peripheral vision )
The human eye can see OUT through the pupil at much wider angles than just seeing the light that comes straight in. So therefore light from a wider angle eyepiece is visible to the eye, and we don't just see light at only the size of the pupil area.
2) Most astronomers will agree that if you like to use a nebula filter (which darkens the view) that a bigger exit pupil eyepiece should be used. (the bigger exit pupil EP lets in more light so the filter works better than in a smaller aperture eye piece)
Doesn't this show that a larger aperture eyepiece lets in MORE light (i.e. works better with a filter)
If it lets in more light, then at the same time I am to believe it lets in less light due to exit pupil limits.
How can both be true?
3) I just don't care. In order to get a huge field of view, I need a larger aperture eye piece.
Don't you want to see the full pliedes? All of the beehive? The double cluster with the star field around it?
Andomeda in its three degree glory?
I observed with a guy that REFUSES to even look into an eyepiece that does not have a proper exit pupil. He literally took three steps back, turned his back on me and said, "that EP you are using won't match anyone's exit pupil". I just got exit pupil snobbed.
Yikes, don't be an exit pupil snob please. Most objects where I want the large field of view are bright objects, so any potential "stop down" is mostly inconsequential. I am typically going to use that low magnification / big FOV eyepiece only a few times a night on some really big targets.
Just enjoy the view and please don't snob me about it. I am not sure I buy the theory anyway.
Yes I have seen the math. I believe the math does not take into account the shape and capacity of the human eye. I believe the math is an oversimplification. In my opinion, "the exit pupil limit" at a minimum makes the view the same brightness as a smaller exit pupil or matching exit pupil eyepiece, but it certainly is not dimmer?
So there you go. Please be understanding to those of us who just want a wide view now and again.
PS - if you feel like responding with the math.....do a self check for exit pupil snobbery....
Edited by Sky_LO, 13 April 2021 - 04:16 PM.