Wide EP's with fast newt's

I have been contemplating getting a nice 2" low power superwide eyepiece around 30mm length for use with my newtonian. The one I have been considering is the 31mm GTO Proxima, which I believe to be an erfle, but I am not sure. I haven't yet had a chance to try anthing longer than a 25mm in my newtonian before, so I have no idea how an eyepiece like this would perform with the fast (f/5) optical system. It is my understanding that longer "ultrawide" eyepieces like this can be problematic in fast newtonians. Is this too long for my telescope? What kind of problems should I expect to experience?

Thanks!

I talked to Gary at HOO about the Proxima for my XT10 f/4.7 and he did not recommend it. Give Gary a call. He is an honest guy and I don't think he would steer you wrong. And I would bet that if you didn't like it, he would take it back.

I bought a Univeristy Konig II 2" 32mm and don't care much for it. It has seagulls starting about 70% on out, and it gets really bad about 90% out. Might not annoy you, but it annoys me. Works fine for a finder ep, but not for a wide field pleasure viewing ep (for me and my scope).

Clear skies,

Tom

I've owned 18" f4.5 and 10" f6 newtonians, both as it happens with rather good early Galaxy mirrors, for quite a few years now. In the f6, the University Konigs of both 32mm and 40mm focal length work pretty well - there's coma, but it's not really noticeable until you're out to about 85% of the way to the edge, and then it really is something you have to be thinking about. Really not annoying at all. My premium eyepieces like the Panoptics and Naglers are nice in this scope, but not necessary to obtain a pleasing view.

In the f4.5 scope, though, the coma is quite obtrusive and very annoying in the Konigs from about 2/3rd of the way to edge on out. Might as well not bother with these in the f 4.5 scope unless you have a paracorr IMO. I never have bought a Paracorr - I use either a 35mm Panoptic or a 31mm Nagler for wide field work in the f4.5, and the coma is well enough corrected to not be terribly obtrusive. The Nagler is better in this respect, but it ought to be for the money!

Only you can decide what your tolerance for aberrations at the field edge is, but most people can readily see the difference and definitely favor the premium eyepieces in the 18. I would urge you to try to test drive your candidates if possible in your f5 scope at a star party if at all possible. I personally think that you'll be happier with a design corrected for the faster scope. Such eyepieces are pricier, but IMO the satisfaction and beautiful wide field views are worth the investment. Most of us are in this hobby for the long haul, and when you consider how long you might be using a high quality eyepiece, the difference between $150 and $300 invested in an essential tool like your widest field eyepiece isn't really all that huge.

I've seen a couple of 35 Pans on sale in the last week for under $275. The Pentax 40mm is nice too, but would give you a rather oversized 8mm exit pupil in an f5 scope...

Clear Skies!

Jim