Plotted entries from OPSLOG files in CRIRES report FLATSTAB, plot 5 (data set plt_par53):
(DATE changes at 21:00 UT or MJD-OBS = xxx.875)
DATE       MJD-OBS      values
====================================================
2010-02-23 55251.452084 0.2582439492
2010-02-24 55252.509249 0.2592725797
2010-02-25 55253.463168 0.2626324802
2010-02-28 55256.399718 0.2551001921