In practice, the error bars are mainly dependent on the magnitude of the object. The information at the top of the screen shows the data extracted from the header record of the intermediate data file. For associated errors, consult the main catalogue. Further details of these data points are given below. The amplitude of the oscillatory motion gives the star's parallax, with the linear component representing the star's proper motion.
Solid circles indicate the inferred position of the object at each observation epoch.
By definition, these fitted points lie on the continuous modelled path. Because the measurement is one-dimensional, the precise location along this position line is undetermined by the observation. The length of this stroke represents the residual of the measurement. Note that the significance of a given residual can only be assessed in terms of the standard error of that measurement. All of these quantities are contained in the intermediate astrometric data file, and form the basis of the statistical plots which can also be accessed.