Thursday, August 20, 2009

Closing Loop on Curvature AO

18 hours after coming back from California, I went over to Maui to work on the Curvature AO system. We re-built the simulator to minimize the number of mounts that were causing alignment drifts. It was actually nice to make a bunch of progress on this type of thing.

Here's the simulator image in-focus. Nice tight point source with the normal diffraction pattern for a cirular aperture with a the normal telescope type obscuration - a secondary mirror with support spiders.

You go through the system and put a voltage on each actuator of the deformable mirror then measure what happens:

This gives you a measure of how each of the 85 actuators changes the wavefront in each of the 85 sensors:
Turn that around (invert the matrix) so you have a measure of how a measurement on a sensor should be corrected with a voltage on the DM:
Mark taught me how to drive the sysem. It's a little scarry knowing that if I screw up the software or forget to block the wave-front sensor I could blow out 85 avalanche photo diodes that cost a few grand each.....


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