Plotted entries from OPSLOG files in ISAAC report FLATLAMP, plot 8 (data set p_M_SK_S):
(DATE changes at 21:00 UT or MJD-OBS = xxx.875)
DATE       	MJD-OBS      	values
====================================================
2013-12-02	56629.816643660000000	13015.740234375
2013-12-02	56629.829208800000000	12199.7400390625
2013-12-02	56629.856923720000000	11635.5404296875