4 Results

The results are listed in Tables 1 to 4 (available electronically via the CDS) in sequence of the HIC numbers of the programme stars. Astrometric standard stars with a HIC number are filed among the programme stars, but can easily be identified by their large number of observations. If they have no HIC number then they are identified by their BD numbers and listed together with 6 additional double stars at the end of the tables. In addition, one photometric standard star, HD214509, turned out to be a close visual double star (last star in all tables) with separation $\rho = 1.241\hbox{$^{\prime\prime}$ }$ and magnitude difference $\Delta V = 2.649$mag. Tables 1 and 3 give summarizing results, whereas the individual observations of the stars that were observed in more than one night are listed in Tables 2 and 4.

Table 1 lists the differential astrometric and photometric results. One can find an identifier, the date of the observation, the total number of observations (N), the mean separation $\rho$ and the mean position angle $\theta$, the number of observations in V (N_V,  N_i) and the (instrumental) magnitude differences $\Delta V$ and $\Delta i$ between the components A and B of the double stars. The values are quoted with their standard error of the mean ($\sigma$). The "distance'' between the binary parameters in V and i (in arcsec) is given in the column r_V,i:

$$r_{V,i} = \sqrt{\rho_{V}^{2} + \rho_{i}^{2} - 2 \rho_{V} \rho_{i} \cos{(\theta_{V} - \theta_{i})}\cdot}$$ (1)

This value is important for the judgement of the quality of the measurements. It will be discussed in the next section.

The distances $r_{{\rm N,H}}$ between the listed observations of the Network (N) and the HIPPARCOS results (H), defined as

$$r_{{\rm N,H}} = \sqrt{\rho_{{\rm N}}^{2} + \rho_{{\rm H}}^{2}... ...m N}} \rho_{\rm H} \cos{(\theta_{{\rm N}} - \theta_{\rm H}})}$$ (2)

are given as well. In general an extremely good agreement is found. A detailed discussion of the comparison with the Hipparcos data will be postponed to a subsequent paper.

Table 3 gives more details of the final photometric results: we list the standard V magnitudes and the colour indices V-I of the components A and B together with the standard errors of the mean on these quantities. Also given are the number of observations in each filter (N_V, N_i) and the differences $\Delta (V-I)$between the colours of the components.

Two systems have secondary components brighter than the primaries in comparison to the designation in earlier catalogues of binaries, i.e. $\Delta V < 0.0$mag, namely HIC44711 (-0.015mag) and HIC80245 (-0.017mag), but this is, of course, filter dependent. In some cases a different faint secondary component was measured instead of the component indicated in earlier catalogues: for example: HIC39056 with $\Delta V = 5.939\, {\rm mag}$.

The magnitude range of the primary components in the sample is mainly $7.5\, {\rm mag} < V\rm _A < 10.0\, {\rm mag}$; one star is brighter and 21 stars are fainter than these limits. Twenty three pairs have instrumental $\Delta V$ values in excess of 3.0 mag reaching a maximum of $\Delta V = 5.939\, {\rm mag}$.

The colour indices V-I of the A components span the range from -0.164 to +3.274mag, i.e. from early B-type to late M-type stars (neglecting possibly present reddening and a few "outliers''). The same holds for the B components where V-I runs from -0.178 to +3.291mag. The differences $\Delta (V-I)$ of the colours V-I of the binary components are negative in 45 systems. Astrophysical implications of this will be discussed in other papers.