We present results from the spectrophotometric calibration of the new E2V CCD camera on the Swope telescope and of RetroCam on the DuPont Telescope. We measured the relative sensitivity of each pixel vs wavelength over the whole wavelength sensitivity range of each camera, for all the filters that will be used during the 5 years of the CSP2 survey. We used a tunable light source and fiber delivery system conceived and built in our lab to achieve +/-1% precision calibration from 300nm to 1100nm and +/-3% from 1100nm to 1800nm. Achieving this relatively high precision at low light levels was made possible by using Si, Ge and InGaAs photodiodes coupled to custom high gain amplifiers. Comparison of these results to results obtained 3 years before, allowed us to confirm that the intrinsic transmission bandpass of the filters has not changed over time but that the mirror reflectivity and the introduction of a new CCD camera drastically changed the total telescope sensitivity. The analysis of the spatial response of the new E2V CCD vs wavelength also shows a slight gradient in the color response of the CCD both in the UV and Infrared.

Date Published: 6 August 2014
PDF: 12 pages
Proc. SPIE 9147, Ground-based and Airborne Instrumentation for Astronomy V, 91475L (6 August 2014); doi: 10.1117/12.2063560

Published in SPIE Proceedings Vol. 9147:
Ground-based and Airborne Instrumentation for Astronomy V
Suzanne K. Ramsay; Ian S. McLean; Hideki Takami, Editor(s)