Celestron Regal F-80ED
You gave this scope a very good review, however, you did have some negatives about the eyepiece. Most of the negatives focused on the build quality as opposed to the optics.
While the negatives focussed on the build quality, as this scope accepts standard telescope eyepieces, would it be possible to increase the optics of this scope by using a high quality eyepiece or would the improvement be only in the build quality? If so, which one?
If one wanted a fixed power eyepiece in the 22-32 X range, which one would you recommend?
Oh, you could very definitely improve optical performance with a high grade, fixed power telescope eyepiece like the Pentax XW 10mm (48x) or a Televue Radian in a similar focal length. My favorite for use in spotting scopes is the Pentax XW - great eye relief, wide field of view and tack sharp to the edge. Not cheap, but oh so sweet an eyepiece.
Just remember, you divide focal length of the scope (480mm on this one) by focal length of the telescope eyepiece (telescope eyepieces are sold by focal length) to get magnification. Easy does it, though - atmospheric seeing conditions put a cap on how magnification you can effectively use. That's why most spotting scopes don't go much over 60x.
I have follow up questions if I may.
Is it also possible to increase the optical performance by using a better zoom eyepiece?
I am under the impression that while it may be possible to physically attach an eyepiece to a particular scope, it may not necessarily be usable as it may not be possible to bring it into focus at the desired range. Is this correct? If so, how does one determine whether or not a particular scope-eyepiece combination will work?
As always, thanks for your advice,
Glad to help
Unfortunately, eyepiece compatibility is an issue on these spotting scopes that use telescope eyepieces and for the same reason that short focal length refractors in the telescope world can be fussy about eyepieces - a spotting scope is actually a short focal length refractor. There is no black and white answer, here. It can be a matter of trial and error. It's one of the valid reasons that spotting scope manufacturers often try to limit you to using their own eyepieces - their eyepieces are made, specifically, for their scopes and that allows them to avoid complaints about using someone else's eyepieces.
However, you are less to have issues on this with fixed power eyepieces and you will certainly have a much better selection if you stick to fixed power eyepieces. In astronomy and telescopes, zoom eyepieces are not widely used or popular; just the opposite of what you find in the spotting scope world.
I do like the Pentax 70509 zoom, but, no, I have not tried it in the Regal. if you buy it, I would make sure you can return it if it does not perform, well, but ti would be my first choice as to one to try.