#zdat (zcalib by M.Zolliker 2018)
#time since midnight, R ref, R meas, sigma
43973.38	35597.14	531.0314	0.0180517035
46103.38	31266.53	511.8478	0.0198563844
52298.33	26855.34	489.9763	0.0184206677
55872.47	21999.25	462.43	0.0220717013
57835.44	17887.59	434.8218	0.0171929055
59797.32	14615.76	408.986	0.0080137382
61773.35	11937.43	383.9905	0.00910302148
70501.47	78.8953	40.41131	0.000994630585
75021.45	71.4666	38.09625	0.000910741456
79360.44	65.09	36.02051	0.000960879805
82890.43	62.0242	34.99008	0.00101141485
85933.45	60.3694	34.42529	0.00123267595