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Re: [ATM] Simple Formula
On Mon, 8 Nov 2004, nunya wrote:
> Hello, All: With all the info I have on my disk (8 megs) I simply cannot
> find the formula for determining the focal length for my (newly coated) 6"
> mirror. The pertinent info I have from the test sheet is as follows:
> optical diameter = 5.83 ROC=89.38 The listed F\D is 7.67 I would like to
> verify this before I begin designing the rest of the OTA. I also have the
> Zonal results and wavefront data, which I would like to send to anyone,
> off-list, who could verify the specifications\quality of the figuring.
> Thanks, in advance. Clear skies to all. John 45.69 degrees north
> 90.39 degrees west
ROC/2 should be close enough, if ROC is of the axial region. It
would be measured from the front surface of the mirror, of course.
This (44.69) more or less agrees (within 0.03") with your stated
diameter and F: ratio.
Dave
--
In each of us, there burns a soul of a woodchuck.
In every generation a few are chosen to prove it.
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