Richard F.L.R. Snashall
rflrs at verizon.net
Sun Mar 27 03:50:35 JST 2011
On 3/25/2011 9:27 PM, Francis J. O'Reilly wrote:
> I have a great piece of BK7, eight inches plus diameter, an inch thick. I need to do something with it. Maybe a Maksutov corrector?
I agree; the corrector would probably need to be sagged.
But you might also consider a BK7 Sandwich:
200 mm f/11.66 Triplet
Surf Radius Thickness Glass Diameter
STO Infinity -4.66032 200
2 1075.218 10 F2 205
3 600 25 BK7 205
4 -600 10 B270 205
5 -15257.47 2302.492 205
IMA -868.0485 44
The risk here is the available quality of B270, but then,
you did not say whether it was really BK7 or just bk7.
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