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Re: advice needed on 40mm UO mk-70 and/or Axiom

Started by Larry Seguin, 03/11/2005 07:59AM
Posted 03/11/2005 07:59AM Opening Post
Hi Nils,
I don't have experience with the Nagler, but I have had the MK-70 for a couple of years now. If you do the math, the MK-70 does have a slightly wider field of view than the Nagler (1.5* compared to 1.3* in my 12.5" f/6). I bought it for the same reaon you mentioned--not willing to spend that much for an eyepiece that sees limited use., Here's some good news though. I'm moving up to a 14" f/4.7 scope, and wanted to know how the eyepiece would look at that f/ratio. Tried it in my friends 17.5" f4.5 and the edge of field was NOT mush, nor was a secondary shadow visible. Cheap, comparitively, and it works great, too!
Larry Seguin
Taos, New MExico
Posted 03/11/2005 10:48AM | Edited 03/11/2005 10:50AM #1
Good to hear there was no secondary shadow. Doesn't the f/ratio become effectively f/6.7, assuming 6mm exit pupil? The effective aperture becomes 10in, and CO goes up by half.

I have a 16.5" project with 3.1" secondary -- wonder if the MK-70 will show the secondary shadow :S

-- William