Plotted entries from OPSLOG files in CRIRES report FLATSTAB, plot 4 (data set plt_par43):
(DATE changes at 21:00 UT or MJD-OBS = xxx.875)
DATE       MJD-OBS      values
====================================================
2010-02-23 55251.450688 0.2797776454
2010-02-24 55252.507824 0.2804708724
2010-02-25 55253.461743 0.2800082704
2010-02-28 55256.398292 0.2768916016