Plotted entries from OPSLOG files in ISAAC report DARK_SW_DC, plot 6 (data set p_R_LR):
(DATE changes at 21:00 UT or MJD-OBS = xxx.875)
DATE       	MJD-OBS      	values
====================================================
2012-02-06	55964.337644	2.52325549374592
2012-02-07	55965.369912	2.49533832227554
2012-02-08	55966.384569	2.54179455876159
2012-02-09	55967.363475	2.54882199937295