Left: based on Hipparcos data (cf. Tables E.2, A.1, and A.2), this example of HD 22049 shows how the relative motion of non-moving background stars in right ascension (solid lines) and declination (dashed lines) will differ from a comoving companion (respective horizontal lines). The lines encompass the Hipparcos uncertainty, scaled by a factor of 100 for visibility. Possible orbital motion of a hypothetical companion has been neglected. The vertical dotted lines highlight the dates of the 1st and 2nd epoch exposures, respectively. The two candidates found are background objects (circles for right ascension and squares for declination; see Table D.1 and Fig. C.1). Right: dynamic range curves for a 10σ detection as a function of angular separation for all exposures of the survey.