HIREX
On-Axis Mirror Analysis
There two main areas of concern that are being examined here:
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The effects of mounting the mirror on its surface,
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The effects of solar illumination on the mirror figure.
The results of mounting studies are outlined below, while the effect of
solar illumination is discussed elsewhere.
On-Axis Mirror Mounting Plan:
The SAO study team has examined the effects of mounting an on-axis mirror
in a mounting system similar to that used
on the TRACE telescope. A much lower preload would be used, for the
initial models the preload was only 44.5 N (10#). Two models were run,
the first looked at the effect of a preload applied directly to the mirror
seat. In the second model an initial mount design was modeled as well.
The resulting predicted surface is shown below:
Pure Clamping (no mount):
With the defect of focus removed, again pure clamping:
It is clear that this method has promise so a mount was added to understand
its effect on the mirror surface.
Mounted Clamping:
With the addition of the mount to the FEA model
yielded the following surface error:
With the focus error removed the surface deflection is given below:
The mount bending results in a >10x increase in the surface deflection,
even after the focus error is removed. A mount design based on a stiffer
clamp will be examined.
Questions, comments pcheimets@cfa.harvard.edu