Plotted entries from OPSLOG files in ISAAC report DARK_SW_DC, plot 1 (data set p_DARK):
(DATE changes at 21:00 UT or MJD-OBS = xxx.875)
DATE       	MJD-OBS      	values
====================================================
2013-05-12	56425.429161750000000	271.300008138021
2013-05-12	56425.469484540000000	271.90000406901