Plotted entries from OPSLOG files in CRIRES report FLATSTAB, plot 6 (data set plt_par63):
(DATE changes at 21:00 UT or MJD-OBS = xxx.875)
DATE       MJD-OBS      values
====================================================
2010-02-23 55251.453447 0.2634434439
2010-02-24 55252.510613 0.2644668691
2010-02-25 55253.464539 0.2636238861
2010-02-28 55256.401092 0.2600279563