#zdat (zcalib by M.Zolliker 2018)
#time since midnight, R ref, R meas, sigma
43665.43	35638.89	11475.46	1.02685929
45795.45	31274.51	10379.87	0.232400516
51990.43	26797.09	9217.92	0.199899975
55564.33	21987.46	7912.76	0.22680388
57527.32	17885.05	6746.2	0.895321171
59489.31	14614.4	5775.9	0.119163753
61465.43	11938.39	4937.559	0.0973185491
70193.39	79.0168	76.8243	0.00145636534
74713.48	71.5521	70.2464	0.001001998
79052.49	65.1589	64.5513	0.000959687449
82582.47	62.0921	61.7972	0.00102761861
85625.43	60.4238	60.2947	0.00103004854