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Originally Posted by Starkler
John B should have an answer to this.
I have the 10.5 and 14mm XL's and havent seen an eyepiece yet that I'd trade them for  |
Well I pretty much agree with Geoff. I have the 7mm,10mm,14mm and 20mm Pentax XW's and I won't be trading them on anything either. The 7mm and 10mm are about as good an eyepiece as I have ever used in these focal lengths and that includes everything uncle Al has ever made. The 14mm has a little bit of field curvature and the 20mm has slightly more field curvature in faster scopes. However, this is a necessary compromise to achieve 20mm of eye-relief and 70 deg AFOV at these focal lengths with this design. It is not obtrusive and you don't notice it in general observing, you can detect it if you specifically look for it. It causes stars in the outer 10% to 15% of the FOV to "bloat" in size by about 5% from best focus. They stay perfectly round and DO NOT become elongated astigmatic slits that are commonplace in $50 eyepieces. The upside is that on axis sharpness, contrast and light transmission are superb and superior to any premium widefield eyepiece I have used.
That having been said the Vixen LVW are also a superb eyepiece. Clearly superior to the LV's that others have mentioned as being great. They are also a completely different design to the LV's FWIW. Any observer would also be very happy to have a box full of Vixen LVW's in his observing kit.
In conclusion I possibly rate the 22mm Vixen LVW as superior to the 20mm Pentax XW. In all of the shorter focal lengths I think the Pentax XW's are about as good as it gets and superior to anything you care to throw at them. I rate them above the Nagler T6's and Radians also by a very small margin.
Whichever you choose between the Pentax XW's and Vixen LVW's you will end up with an excellent eyepiece. So don't get involved too deep in "paralysis by analsysis". If you can afford the shorter focal length Pentax XW's grab 'em, if not take comfort from the fact that the Vixen LVW's are also superb. Something else that may be important to you depending on the scopes you own is that the LVW's all have the dual 1.25"/2" barrel and fit either size focuser. This is no benefit to me but may be relevant to you.
CS-John B