Re: [ATM] Gimbaled Secondary mirror

["Richard F.L.R. Snashall" <rflrs@rcn.com>]

Richard wrote:

>Hi atm,
>
>Thursday, June 30, 2005, 10:15:21 AM, you wrote:
>
>aho> I've run this through OSLO and CODEV and I don't see any appreciable change
>aho> in aberration for the various back foci.
>
>I have to say I'm with Dave on this one. I've ray traced the
>design spec on your web page and I find moving the secondary by
>20mm does reduce the back focus from 640.5mm to 449.5mm, but at
>the expense of reducing the Strehl from 0.983 to 0.614. That
>said, I can't duplicate your stated F/# or focal length from
>your spec either, so I may have made an error.
>
>
Given the aperture of 24, primary focal length of 127.22, the
final focal length of 381.33, and the BFL of 25.81, just
running the numbers through the design tool give errors in
all aspects of the secondary.  For a classical (the site author
doesn't give the primary conic constant, so I assumed -1), the
separation should be 88.938, the radius should be 114.897, and
the conic constant should be -4.005.  Perhaps the numbers given
reflect some form of measured values instead of design values...
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