Quote:
Originally Posted by Kal
For optimal deep sky observing the general concensus is 2-3mm exit pupil, which would put you in the realm of a 10-15mm focal length eyepiece. Which eyepiece in this range depends on your budget and observing preferences, for example, do you like a large field of view?
|
I agree with Kal (Andrew) here.
What you need to do is not waste any light by a larger exit pupil, and not be able to see enough of it with a smaller one.
Maintain a good exit pupil which depends on you individually (Everyone has a different size) with age etc, then calculate the required eye piece focal length.
You can afford some magnification and in fact you need it, as it will reduce the contrast of the light pollution, and the contrast of the galaxy or DSO will stay mainly the same, in the field of view. Do a search and read about it.
Theo.