Pentax 40 XW?

I've tried to find an affordable maximum-field 2" eyepiece. It seems that I
either get field curvature or astigmatism in the ones I've used, even at f8
and higher. These include the Widescan III, the MK-70 and the Pentax XL
40mm. So, maybe its time to try a more complex design.
I'm thinking the 40mm XW is the next step up. Agreed? Have you tried it or
know of a decent review?

I have not tried the 40XW but as you stated the 40XL did have some problems that are found in reviews.
I think that most Wide Field EPs of the 30-40mm size will bring out the coma in the mirror of most scopes. Astigmatism however is just a poor design.
I would say that the 40XW might be a good bet, but you might have noticed a few for sale here recently. I don't know if this indicates that the problem still exists or not.
I can say that the 31mm Nagler is very nice and the 40mm Panoptic is as well. However even the best EPs won't eliminate problems in the optical train, so if the problem is in the eye or the optics the EP will not correct it.
I for one would love to try the 40XW. I like the XW 5.2-14mm very much. The 5mm XW is great, but I have never used the longer F/L XL's or XW's.
Floyd

Ed,

Is there any possibility that you have uncorrected astigmatism that comes to the fore with the larger exit pupils a 40mm eyepiece gives you? I have no idea how common this is but I have astigmatism problems with eyepieces that give more than 3mm of exit pupil, even using my glasses (which include a correction for cylinder).

Just a thought...

John

Hi Ed,

I used a Pentax XL40 for several years, and was never satisfied with either its off-axis performance or its contrast. I sold it a few months ago, and got the Pentax XW40. The XW40 is a huge improvement in both contrast and off-axis astigmatism and a definite keeper. Its an outstanding eyepiece in my opinion.

Jay

Was considering a Panoptic 41 but based on my positive experience with the 20mm XW I purchased the 40mm XW 2 last weekend. My scope is a LX200 14". Great views, edge-to-edge. Expensive, but worth it. I also have a 31mm Nagler.

HI Ed,

I own the 40mm XW and find it to be an excellent performer in everything- a 10" F/5 Portaball, FS-152 Takahashi, 12.5" dobson and an 8" F/12 D&G. Feel free to e-mail me re: questions.

[email protected]