Bright and wide FOV, how?

[MiG]

Is it possible to use a field reducer or some other sort of lens arrangement to get a low magnification on a large telescope while maintaining a 6 mm exit pupil?
Example: On my 250 mm Dob, a 30 mm EP gives 41.7 mag and a 6 mm exit pupil. A 60 mm EP would give 20.9 x mag with a 12 mm exit pupil. This would suck. How can you get that magnification with a normal exit pupil on a big scope?

In other words, how do you get a bright and wide FOV?

[Starkler (Geoff)]

Aperture / magnification = exit pupil size.

So for a given exit pupil size, you need to decrease the aperture if you want to decrease the magnification.
Sorry its just physics.

You can however get a wider FOV by using a widefield eyepiece design such a nagler whilst maintaining exit pupil size.

[[1ponders] (Paul)]

Besides with anything more than 5-6mm you would be loosing brightness as the average persons pupil dilation is around 5 mm or less in adults. Therefore if you have an exit pupil of 12 mm then only one quarter of the light will enter your pupil (1/r square law, ie for every doubling of radius the intensity will be 1/4)

[Robby]

Televue Nagler or Panoptic, but that means $$$
Good luck

[MiG]

Originally posted by [1ponders]
Besides with anything more than 5-6mm you would be loosing brightness as the average persons pupil dilation is around 5 mm or less in adults. Therefore if you have an exit pupil of 12 mm then only one quarter of the light will enter your pupil (1/r square law, ie for every doubling of radius the intensity will be 1/4)

Well, that's the thing. I'm asking whether you can keep the 6 mm exit pupil and have a low magnification.