Re: ATM Off axis Parabolas

[Andy Saulietis <iss@pvtnetworks.net>]

Guy B writes,

>How do they make those segmented mirrors found in many large (8-meter
>and such) telescopes?
>Are they all congruent, or are they off axis paraboloids?

Some are segments of hyperboloids in warping mounts,
others are thin enough to use active figure control
via piezo actuators. Paraboloids are not common at
the low f ratios in these sizes because of coma etc.

The largest of thes is the 10/11 meter Ebberley photometric
telescope at McDonald Observatory in W Texas, look up their
web site for details.




Andy Saulietis
ISS Enterprises
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e-mail: iss@pvtnetworks.net