3 Results

The $uvby\beta$ data are presented as plain averages of the values obtained in individual nights. Since a complete standard system is set up each night no night corrections are applied. Tables 1-3 contain the observations for the three directions, but only for stars with $\beta$> 2.580.

The characteristics of the sample is demonstrated in Figs. 1-4. The first of which is the (b-y) - c₁ diagram. Standard lines are drawn as

  

Figure 1: Combined b-y - c1 diagram for the three shadow directions. lb165-32 ($\diamond$), lb27-31 ($\bigtriangleup$), lb329+46 ($\times$). Solid curves are standard lines, $\delta m_1$ and $\delta c_1$ both equals 0. Dashed curves BHB, RHB and the AGB. GB indicated for two metallicities

solid curves, the small gaps mark discontinuities between imA and A, and between A and F stars, and are taken from Crawford (1975, 1978, 1979), Hilditch et al. (1983) and Olsen (1984). The dashed curves indicate, from blue to red, blue horizontal branch , red horizontal branch rising in the asymptotic giant branch, the gap between is populated by RR Lyrae stars. The BHB is from Hill et al. (1982), the RHB, AGB and GBs are from Anthony-Twarog & Twarog (1994). The reddening free [m₁] - [c₁] diagram is displayed in Fig. 2 and we notice that the F stars are shifted to the metal weak side

  

Figure 2: Reddening free [m1] - [c1] diagram. Coding as in Fig. 1

and that the A star range contains a number of metal rich candidates. Due to the presence of the shadows the three regions are known to contain reddening material and Fig. 3 accordingly shows that most of the stars are shifted

  

Figure 3: $\beta - b-y$ diagram. $\beta$ reddening free

to the red side of the standard relation in the $\beta - (b-y)$ diagram. There is however a number of F stars shifted to the blue side, this could be due to a low metal content. So a substantial number of metal weak stars is expected, this was perhaps to be anticipated from the three fields galactic latitude. Figure 4, a reddening free diagram, confirms that the sample contains

  

Figure 4: $\beta - [m_1]$ diagramme. Stars with small [m1] values compared to the standard curve are metal weak, those with larger [m1] values may be metal rich. The A star range apparently contains a number of metal rich candidates

many metal weak stars among the late Fs, they have small [m₁] values compared to the value on the standard curve for a given $\beta$ value. More surprisingly, the sample contains quite a number of metal rich candidates in the A star range. Metal rich A stars have larger [m₁] than the standard curve values. A very extreme one is noticed.

The precision of the data is evaluated from multiple observations. Most stars are observed three times in uvby and $\beta$. The error of the mean of V, b-y, m₁, c₁ and $\beta$ for one star is 0.011, 0.005, 0.008, 0.009 and 0.006 mag respectively. $\sigma _V$ and $\sigma _{c _1}$ are marginally smaller than usual: 0.016 and 0.012. Error propagation of such errors provide $\sigma _{E(b-y)}$ of the order of 0.008 and $\sigma _{dst}$/dst = 15$\%$, (Knude 1978). The distance precision is in agreement with the result from a comparison of photometric distances to Hipparcos parallaxes for the $\sim$20 stars in common, see Sect. 4.

Our data accuracy may be checked to published data, Hauck & Mermilliod (1990). Table 4 displays the outcome, for a small number of stars though. There is one outlayer in c₁ and the mean deviation in $\beta$ is a little large. Assuming identical intrinsic standard deviations in our data and the published ones, we may check our intrinsic accuracy: 0.008, 0.006, 0.008, 0.015 and 0.006 in V, b-y, m₁, c₁ and $\beta$ respectively. $\sigma _V$ is lower than expected, otherwise these numbers confirm the accuracy expected from integration time and number of observations decided at the telescope. c₁ and $\beta$ are both essential for the derivation of M_V and E_b-y.

  

Table 4: Differences in the sense this catalog - Hauck & Mermilliod (1990). In 0.001 mag