These are wavelength calibrations that are measured typically during the afternoon with ThAr in one fibre and Fabry-Perot (FP) in the other fibre. The FP lines are compared to a reference (typically from the morning calibrations) and a shift in pixels is determined. This shift is converted into a radial velocity precision, 0.002 pixels correspond to 1 m/s, and devided by the time difference to the reference.
Plots 1, 2, 5, and 6 show the shift in pixels; plots 3, 4, 7, and 8 the converted values in cm/s/h. Only measurements where the time difference to the FP reference is at least one hour are plotted.
Downloaded values are always in pixels, the conversion to cm/s/h is done internally. Also all measurements are available including values where the time difference is less than one hour. This can be checked with the delta_time_fp column that has the time difference in fractions of day.