Has anyone used the GSO Kellners?
I about to build a 6"f12 refractor using an Istar objective and realise my eyepiece collection is full of shorter FL ones that are a bit on the low end of exit pupil range.
I am thinking also of the ES 68º range, have the 40mm (thanks Astro Bot) and have had 16 20 and 28 in the past, also very nice. The entire set does cost a bit but the GSO's are a lot cheaper. I have a couple of RKE's that I like a lot at f8, so does that mean the GSO Kellners are good too at f12?
I'l be able to answer all this when the scope is built but until then would like to hear what you think? Superviews are also on the list.
Matt
I agree with Brian. The 40mm is great and I sold the TV55mm plossl because I like the 40mm GSO Reverse kellner more. It is fine at f12 and f15. The 26mm GSO is not too bad but I tend to go for the 24 Panoptic mostly. Haven't tried the 32mm GSO.
I have had the 15mm Superview too and agree they are amazing value. Looking at myastro shop site the Prostar 70º eyepieces are also cheapish and have 5 elements. I have the Agena Astro version of these in 15 and 20mm for bino's and they are really good.
I have read the Kelleners have terrific light through put, mostly due to three elements and the RKE's are like that too.
Seems at f12 nearly anything will work well. Can't wait to get this scope on the road...weather permitting.
Superview, Kellener, ES 68º, Prostar SWA....spoilt for choice.
They will work well at f12 Matt , give good images , wax light thru-put and for the price 
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