Previous Calibration reports of VIMS

IR Wavelength Calibration 8/10/15

VIMS' IR wavelength calibration has been observed to be drifting toward longer wavelengths over the roughly 10 years since the start of the Cassini orbital tour. The shift amounts to about 9 nm, or about 0.6 channels over the roughly 10.5 years since the start of the Cassini orbital tour. The reasons for the shift are unknown at present. The shift was detected and quantified by observing changes in the peaks of the atmospheric transmission windows in Titan's reflectance spectrum in the near infrared. Since the wavelength shift was recognized, the VIMS team has initiated wavelength calibration checks using the internal calibration diode built into the IR channel. As of November 2014, the drift toward longer wavelengths in the VIMS IR channel continues. Going forward from approximately June, 2014, the wavelength calibration of VIMS will be determined solely using its internal calibration diode. The present plan has the VIMS team performing diode calibrations every few days throughout the rest of the Cassini mission, starting approximately June 2014. See the current spreadsheet of results.

Cassini Visual and Infrared Mapping Spectrometer (VIMS) Radiometric Calibration 10/16/2016

We derive VIMS Radiometric Calibration, RC19, and project to the end of mission:
Clark et al. (2016) The VIMS Wavelength and Radiometric Calibration. The calibration data files are in a gziped tar file Since entering orbit in 2004, the VIMS instrument has undergone small shifts in the wavelength calibration of the spectrometer. The maximum shift is currently 10.4 nm (0.65 channels) and is estimated to be 0.71 channels at the end of mission. The wavelength shifts now require a time-dependent radiometric calibration technique to be deployed to preserve radiometric accuracy.