Friday, March 5, 2010

Tidying up our M2 interferograms

Having the Faro set up within reach of all the M2 test gear has made it possible to significantly improve our alignment of the null lens & interferometer with respect to M2. 


This has led to cleaner interferograms &, consequently, a growing sense that this just might work - rather well in fact if the preliminary Durango (interferometer software) results are anything to go by...


The interferograms below show the effects of various adjustments made to the null lens & interferometer (including its reference mirror).  Our best M2 wavefront so far - similar to that shown in the right-hand image below - had a RMS of 0.18 waves.

  

The original SAGEM interferogram for M2 was good to nearly 1/20th of a wave RMS.  We hope to achieve a similar result, but this may be overly optimistic given that M2 was still a "free range" mirror at that stage - it had yet to be mounted in the SAC cage...

 

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