Illustration of the χ² maps for those 20 stars for which the astrometric orbit could be detected in the Hipparcos data, as a function of inclination and ascending node. The contours show the 1σ, 2σ and 3σ confidence regions in both parameters jointly. Please note that for ρ CrB b the allowed range in inclination is so small that it is barely visible in this representation; the corresponding data can be found in Table 2.