Plotted entries from OPSLOG files in CRIRES report DARKRON, plot 4 (data set med_par_ch4):
(DATE changes at 21:00 UT or MJD-OBS = xxx.875)
DATE       	MJD-OBS		det_ID     	values
====================================================
2012-02-06	55964.350696	CHIP4.INT1	4.05498755400265
2012-02-07	55965.362876	CHIP4.INT1	3.99773915132823
2012-02-08	55966.361689	CHIP4.INT1	3.99391200729388
2012-02-10	55968.437095	CHIP4.INT1	4.02818687945144