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.