- TO.2: The delivered PSF from the telescope, instrument, and other factors exclusive of the site seeing will be no greater than 0.55 arcsec FWHM (DES-doc-806-v25).
- R-18: The PSF FWHM in each of the r, i, and z bands should, over all exposures and over the survey area, have a median of less than 0.9”. Moreover, for 95% of the survey area, there should be at least one exposure in each of these bands for which the mean PSF FWHM is 0.9” or smaller (DES-doc-20-v32).
Procedures:1. Check TO.2:
- When pointing to the Zenith, the PSF FWHM from DECam are compared to the CTIO DIMM seeing measurements according to the model FWHM^2 = DIMM^2 + \sigma^2. The best fit value is \sigma <= 0.55" across the full array. Therefore, we can measure the contribution of the PSF from the DECam by subtracting the DIMM seeing from the measured PSF by quadrature.
- Step 1: