Nobody has mentioned the meade 14mm UWA series 4000
This is one that I myself own and it is a KILLER eyepiece!!!!...super, ultra-flat view from edge to edge in my 12"F/5 GSO telescope!!!, Blows the 12mm Nagler Type 4 away on sharpness too !!!
I would have to disagree that the Naglers are "better" then the Pentaxes. I love the naglers, don't get me wrong, they have a nice 82 degree FOV, but the Pentax XW's from 10mm up are super-sharp and the edge performance on these babies are far superior to the Naglers!!!
I just got my 10mm Pentax XW in the mail yesterday and alreay had it trained on Venus this week for a quick view!!!
I also think that the 9mm nagler Type 1 has better eye relief then the newer 9mm Nag type 6.
All in all, the naglers are great workhorse eyepieces, but there are also others to pick from besides just them.
I would LOVE to have a look through that 31mm nagler, I'll tell you that for sure!!!!
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Mark
12" F/5 GSO Telescope
30mm 1rpd (coming soon)
14mm meade series 4000 UWA
10mm Pentax XW
2" GSO Barlow