6 Description of the catalogue

Section 3 describes the stellar contents of the catalogue. It consists of a main catalogue with $98\,482$ entries and a supplement with 4777 entries, as detailed in Table 1, and is available from the astronomical data centres, accompanied by a detailed format description. Here we give only a summary of the contents.

• Running number, $1\ldots65\,210$, for the system. Please note that some systems are split between main catalogue and supplement, and some are in fact only in the supplement;
• a unique component designation. As far as possible consistent with WDS designations;
• number of components, $0\ldots11$, in the main catalogue and in the supplement for the system;
• RA and Dec (ICRS) at the epoch of observation ($\sim$1991.5). A flag indicates whether the position is from the new reduction (50%) or is copied from Tycho-2 (50%). For the supplement, the position is either copied from Tycho-1 (21%) or copied from Hipparcos (79%);
• proper motions. A flag indicates if it is copied from Tycho-2 and valid for the photocentre (47%) or valid for the individual component (49%). For 4% no proper motion is available and for 0.03% it is copied from Hipparcos;
• $B_{\rm T}$ and $V_{\rm T}$ photometry is provided for all stars in the main catalogue and for many stars in the supplement. For the remaining stars the Hipparcos magnitude (Hp) is given. A flag details the several possible sources of the photometry;
• Tycho-2 identification with new TYC3 numbers for the fainter component of newly resolved stars. Only three double stars are not in Tycho-2 at all, as explained in Sect. 3.1;
• cross identifications to WDS, Hipparcos (including component letters) and HD. The latter is taken from Fabricius et al. (2002);
• position angle and separation are provided relative to a previously listed component of the same system. They are computed for the mean observational epoch of the two stars. Position angles are given with respect to the ICRS pole;
• a note is given for some stars to explain peculiarities, mostly due to complications with the WDS identification.

Acknowledgements

This work was supported by the Danish Space Board. Thanks are provided to the U.S. Naval Observatory for their continued support of the double star program.