SERTS will provide in-flight radiometric and wavelength calibrations for several instruments onboard the SOHO spacecraft by making simultaneous coordinated observations of the Sun with SOHO at selected times during the mission. The SERTS wavelength scale is routinely determined to an accuracy of about 1 mA from pre- and post-flight tests done at GSFC using well known lines of He II and Ne II. Now in addition, just before or after each rocket flight, we will carry out radiometric calibrations of the full SERTS instrument at the Rutherford-Appleton Laboratory (RAL) in England, using the same vacuum facility and EUV radiation source that was used in the original pre-flight calibration of the SOHO/CDS experiment. The light source itself was specially developed by the Physikalisch-Technische Bundesanstalt (PTB) in Germany, and incorporates a back-up SERTS telescope (provided by GSFC) used in inverted mode as a collimator. Formal agreements are in place with RAL, PTB, and the SOHO project to support ongoing SOHO/SERTS calibration efforts.

The end-to-end calibration of SERTS will continue. Each time SERTS is flown it will be calibrated at the Rutherford facility. The existing test fixture will be modified to accommodate changes to the SERTS instrument such as the incorporation of the multilayer telescope. These data will provide valuable checks on the calibration of CDS as well as improving the quality of science from SERTS spectra.

 

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Last Revised: Wednesday, 29-Nov-2006 07:36:52 EST

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