Widest True Field?

I have an ETX-125, and I'm looking for the best "finder" eyepiece for it - that is, the eyepiece that will give the widest true field.

I currently have a TV 32mm Plossl that I'm pretty happy with, but recent discussions on Usenet have pointed me toward the Celestron Ultima/Parks Gold/Orion Ultrascopic 35mm, which would (theoretically) have a wider FOV. However, I know that actual FOV is dependent on the field stop, and most manufacturers don't actually provide that info.

Along the same lines, I did some checking on the UO 32mm Konig, which (they claim) has a 34mm "clear aperture" and a 52* FOV. Not sure how "clear aperture" relates to field stop, but again, this EP would theoretically give a slightly wider field than the TV. Where can I get a decent price on UO EPs, by the way?

I'm primarily trying to minimize the inherently narrow FOV of the ETX by getting the widest field possible out of my EPs (I have a Pentax 14mm, working on getting a 21mm). Eye relief is also an issue, since I do wear glasses. The TV works pretty well with the eyecup folded down, and I know from comments on Excelsis that the eye relief on the 35mm is perhaps too long for people who don't wear glasses, but seems quite nice for those that do. The UO Konig is supposed to have decent ER as well, from what I've read.

Any info, clarifications, or recommendations gladly accepted - while the TV is nice, I've only really compared it to a Meade 24.5 SWA, which didn't have enough eye relief for me.

For a distributor of UO eyepieces try
http://www.helix-mfg.com/eyepieces.htm

or go to UO
http://www.universityoptics.com/uoep.htm#.

The maximum field of view in any 1 1/4" eyepiece is limited by the field stop. The outside diameter of the 1 1/4" sleeve is 31.75mm. The largest the field stop can be is limited by the thickness of the sleeve wall, a few mm. The widest field stop I've ever measured is 27.4mm, for a Celestron 40mm plossl. My TV 40mm plossl measures 27.3mm. The Celestron Ultima 30mm is 26.1mm. The difference between these is 66arcmin for the Ultima versus 69arcmin for the 40s in my scope, less than 5%. The big difference is that the 30mm, with only a 5% smaller fov provides 35% higher magnification and makes things much easier to see.

The Meade 24mm SWA is advertised as 68° afov. In my scope that would produce a 72 arcmin True fov. In order for that to really happen the field stop in the 24SWA would need to be 28.5mm. I don't own one, but I'll go out on a limb and say, I't ain't so. (Anybody want to turn their 24SWA upside down and measure the field stop. Got calipers? I bet it's no more than 27.5mm). I do own the 18mm SWA. The Tfov that it really produces indicates that it is not 68° afov but is really only 63° afov. I suspect the 24mmSWA is similar, maybe up to 65° afov. The point is, the 24SWA can only equal the Tfov of the largest possible field stop, not exceed it. The benefit would be that it does it at a much higher magnification.

If I were you I'd be more concerned with picking an eyepiece that doesn't have a tendency to kidney bean, or black out on me as I moved my eye around. From what I've read, both the 35mm Ultima and the 32mm Konig might fall into that category. I'd want to pick an eyepiece that is easy to hold the view and doesn't have eye relief so far back that I can't find the right place to keep my eyes.

Clear aperture is the diameter of the eye lens, nice, but no benefit to field of view. The 30mm ultima has a 30mm clear aperture. The 40mm TV plossl has a 26mm clear aperture.

edz