Plotted entries from OPSLOG files in ISAAC report GRAT_SW, plot 4 (data set p_F):
(DATE changes at 21:00 UT or MJD-OBS = xxx.875)
DATE       	MJD-OBS      	values
====================================================
2012-05-20	56068.858148	2444634
2012-05-20	56068.858786	2456807
2012-05-20	56068.859422	2459013
2012-05-20	56068.860058	2422683
2012-05-21	56069.851617	2433481
2012-05-21	56069.852255	2459248
2012-05-21	56069.852892	2435306
2012-05-21	56069.853528	2412186
2012-05-22	56070.859147	2476499
2012-05-22	56070.859783	2469106
2012-05-22	56070.860419	2469532
2012-05-22	56070.861055	2422420