After averaging the point data, we should pay attention first to the astrometry, i.e. the quality of the delay data and the station coordinates. ... Plot FDL_O-C, that is the observed minus calculated FDL delays, versus time. ... The reference station can actually be changed in the Calibrate|Astrometry|SOLVE menu. ... This figure shows the residual delays for station 2 after solving for station coordinates, using the widget displayed in the lower right of the figure. ... Back to tour page . ...