Motion of an SSO: a linear weighted-least-squares linear fit of the motion of an SSO in right ascension (top) and declination (bottom). The blue dots represent the positions and the solid lines the linear fits. The shaded blue areas mark the 95% confidence interval. The positional errors are the errors on the centroid computation performed by SExtractor. In the upperplot, the errors on the right ascension are smaller than the symbol sizes.