#zdat (zcalib by M.Zolliker 2018)
#time since midnight, R ref, R meas, sigma
43486.32	35629.46	64485.6	18.1885678
45616.31	31267.73	55680.4	9.77875248
51811.47	26777.32	46824.12	3.90314745
55385.45	21975.83	37543.38	3.22969968
57348.32	17875.2	29827.89	2.58710069
59310.42	14612.01	23852.06	1.18812457
61286.32	11937.55	19067.14	0.960541514
70014.32	79.097	96.1207	0.00163125718
74534.34	71.6141	86.872	0.0023194827
78873.39	65.2109	78.9762	0.00125538839
82403.38	62.1421	75.1966	0.00134313067
85446.33	60.4638	73.129	0.00152970585