[ ESO ]

Comparing DIMM Seeing to FORS Image Quality

ATACAMA WORKSHOP, Ithaca NY
M. Sarazin, June 15-17 2000, 6/14

DIMM converts image motion into large telescope seeing with the assumption of an infinite outer scale of the turbulence. UT images turned out about 10% better than predicted by DIMM, confirming the finite character of the outer scale. Correcting for that effect is possible by removing from the DIMM the share of the tilt of an 8m aperture.

Comparison of DIMM seeing (Y axis) after correction for outer scale, with FORS Science Verification (SV) Image Quality (X axis) as processed by the SV team, corrected for zenith and 500nm.