#zdat (zcalib by M.Zolliker 2018)
#time since midnight, R ref, R meas, sigma
44229.32	35579.69	10570.03	0.341189097
46359.31	31243.88	9567.86	0.115065199
52554.34	26878.88	8526.18	0.564233994
56128.32	22003.46	7312.82	0.212037732
58091.46	17883.93	6237.02	0.11296017
60053.37	14617.38	5342.18	0.417085123
62029.32	11939.03	4568.682	0.115306548
70757.33	78.7986	74.2009	0.000994484791
75277.32	71.3971	68.0835	0.000886002257
79616.32	65.0359	62.7663	0.000693541635
83157.32	61.9687	60.183	0.0010198039
86189.34	60.3267	58.7945	0.000324037035