Plotted entries from OPSLOG files in FORS2 report ZEROPOINTS_R, plot 4 (data set pars2):
(DATE changes at 21:00 UT or MJD-OBS = xxx.875)
DATE       	MJD-OBS      	values
====================================================
2012-05-15	56063.206417	0.00503223188788318
2012-05-15	56063.212055	0.00848297519562152
2012-05-16	56064.377146	0.00527915015904731
2012-05-17	56064.990246	0.00388261646994928
2012-05-17	56064.995389	0.00375650481155179
2012-05-17	56065.206566	0.00536915214912847
2012-05-17	56065.424951	0.00460288366328281
2012-05-18	56065.959893	0.00369296794045037
2012-05-18	56065.964445	0.00379219640335773
2012-05-18	56066.220857	0.00491672776471323
2012-05-19	56066.953624	0.00382715710906125
2012-05-19	56066.959075	0.00425773281301873
2012-05-19	56067.210122	0
2012-05-20	56067.971947	0.00366474340523935
2012-05-20	56067.977104	0.00409713178872205
2012-05-20	56068.185862	0.00565162298107218
2012-05-20	56068.275485	0.00527111970236885
2012-05-21	56069.029709	0.00381068391231571
2012-05-23	56070.942474	0.00943603657738731
2012-05-23	56070.951192	0