Plotted entries from OPSLOG files in ISAAC report DAYCALSLIT, plot 4 (data set p_AF):
(DATE changes at 21:00 UT or MJD-OBS = xxx.875)
DATE       	MJD-OBS      	values
====================================================
2012-05-18	56066.499871	2796106

Plotted entries from OPSLOG files in ISAAC report DAYCALSLIT, plot 4 (data set p_BF):
(DATE changes at 21:00 UT or MJD-OBS = xxx.875)
DATE       	MJD-OBS      	values
====================================================
2012-05-18	56066.489344	2792825