#zdat (zcalib by M.Zolliker 2018)
#time since midnight, R ref, R meas, sigma
44152.38	35591.99	46945.11	2.82093779
46282.37	31247.74	40920.14	7.05742446
52477.31	26860.5	34920.3	18.501908
56051.45	22002.38	28291.05	2.38127067
58014.30	17883.25	22757.8	3.36193397
59976.31	14615.54	18433.48	4.434023
61952.37	11938.86	14910.82	1.01732984
70680.44	78.8249	91.262	0.001356466
75200.43	71.4159	82.7178	0.00166613325
79539.33	65.0488	75.3761	0.0012365274
83069.32	61.9834	71.8375	0.00104163333
86112.40	60.3381	69.9359	0.00092141196