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From: George Huxtable (no email)
Date: Sun Nov 02 2003 - 14:04:26 EST
Geoffrey Kolbe wrote-
>For those following this particular thread, I will just come back and
>defend my analysis of Kieran Kelly's problem, to which George took exception.
>
>George's analysis is quite correct, as far as it goes, but I think his
>analysis is too simplistic. He has taken a very particular scenario for the
>topology of the mirror, (which we do not know). When he says he has chosen
>dished or spherical shape, he has in fact analysed it as a cylindrical form.
No, it was INTENDED to deal with the spherical case and I think it does so.
It also covers the case of cylindrical distortion, or its component of
curvature along the azimuth in which a sextant altitude is measured.
>
>I think that if a weighted analysis was done over the possible topologies
>of the mirror, it would turn out in the end to be quite similar to the
>resolution analysis which I used. I think such an analysis would return a
>quite similar result in the order of 0.1 arc-minute for the mean angular
>deviation we should expect for a random 2cm diameter section of a mirror
>having diameter 14cm and flat to 7 wavelengths. I may be out by a factor of
>two or so, but I would be surprised if it was more than that.
Geoff and I have looked at this matter from rather different viewpoints and
have arrived at rather similar conclusions, and I am happy to shake hands
with him about that.
>That said, George and I both agree that Kieran should not worry about the
>flatness of his mirror.
We concur!
George.
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contact George Huxtable by email at , by phone at
01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
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