2.2  Radiometric Calibration

Figure 9: [from Del Zanna 1999] The proposed CDS NIS 1 sensitivity (solid line), compared with the other calibrations. The asterisks indicate the scaled values of the sensitivities, as derived from ratios of lines of the same ion observed within this detector.

This is an essential requirement. An entire book could be written on this issue. For details on the calibration of the SOHO instruments, see The Radiometric Calibration of SOHO, ISSI Scientific Report, 2002, Pauluhn,A., Huber M.C.E., von Steiger,R. eds.

To understand the complexities of the CDS calibration read the first (and still only) comprehensive in-flight calibration work:

Del Zanna, G., et al., 2001, A&A 379, 708-734. Solar EUV spectroscopic observations with SOHO/CDS. I. An in-flight calibration study and my WWW pages:

http://www.damtp.cam.ac.uk/user/astro/gd232/cds/