Stephen Kent, 07/19/2012 02:59 PM
Optical prescription, fabrication errors, alignment errors, flexure, and CCD non-planarity contribute no more than ???? waves RMS (or ??? FHWM) to images taken at best-focus position [DECam TO-2 (see Table 2 for budget), TO-4] To be tested over full HA/Dec range of Survey.
The idea is to test as many line-item contributions to the PSF budget as possible. In practice we can probably do the following:
* Focal plane height varies by <= 30 microns peak-peak.
* Primary mirror figure / Corrector design / static alignment / flexure contribute <= ??? waves RMS.
* Same as for IQ-R1
* Use the same science CCD images as for IQ-R1.
* Reanalyze images but incorporate higher-order Zernike terms in the fit.
* Subtract out field patterns in coma, astigmatism that could be attributed to misalignment or primary mirror astigmatism. (Alternatively, extract all azimuthally-symmetric Zernike patterns)
* Compute wave-front error from all remaining Zernikes.