Plotted entries from OPSLOG files in NACO report DAILY_DARKRON, plot 2 (data set ronFNS3_HC):
(DATE changes at 21:00 UT or MJD-OBS = xxx.875)
DATE       	MJD-OBS      	values
====================================================
2013-05-17	56430.365421450000000	2.34316058412607
2013-05-18	56431.358305680000000	2.44062605038247