Plotted entries from OPSLOG files in NACO report DAILY_DARKRON, plot 6 (data set darkFNS1_HC):
(DATE changes at 21:00 UT or MJD-OBS = xxx.875)
DATE       	MJD-OBS      	values
====================================================
2013-05-14	56427.492232500000000	-0.96875
2013-05-15	56428.479312600000000	-1.125
2013-05-16	56429.369909360000000	-1.03125
2013-05-17	56430.372909740000000	-1.0625