#zdat (zcalib by M.Zolliker 2018)
#time since midnight, R ref, R meas, sigma
44306.33	35564.12	64329.9	42.2973876
46436.35	31236.38	55693.7	57.3177198
52631.47	26895.28	47045.08	4.49986222
56205.45	22007.27	37598.86	1.8429433
58168.30	17883.03	29835.94	3.11246526
60130.44	14617	23855.81	1.96562713
62106.32	11938.29	19074.16	6.79910582
70834.31	78.7734	95.7187	0.00175527776
75354.33	71.3795	86.585	0.00127279221
79693.46	65.0238	78.7444	0.00171580885
83234.30	61.9555	74.9667	0.0014216188
86266.32	60.3165	72.9488	0.00196367003