4 Results

From Feb. 23, 1992 to Mar. 31, 1997, there are about 405700 observations of stars over 1532 days. From these data, 11002 residuals are obtained with a mean precision of $\pm$0.043''. 5241 position corrections of stars have been obtained using Eqs. (4) and (5) from double transits of these stars at both their eastern and western passages with average precisions $\pm$3.2 ms and $\pm0.057''$ in right ascension and declination, respectively. The unknown terms $\xi$ and $l\cos\delta$ included in the computed $\Delta\alpha$ and $\Delta\delta$ are neglected. The $\Delta\delta$ for the stars with $\vert\cos q\vert<0.3$ are not computed.

4.1 The relation between residual and magnitude

The mean values of residuals of stars by weighted mean according to the precision of residuals and magnitudes are given in Table 1. In Table 1, $\bar{M_v}$ is the mean values of the observed magnitudes, N is the number of observed stars, $\bar{V}_{\rm m}$ and $m_{\bar{V}_{\rm m}}$ are the mean value of residuals and its accuracy.

4.2 The relation between residuals and spectral types

The mean values of residuals of stars obtained by a weighted mean according to the precision of residuals and spectral type are given in Table 2. In Table 2, N is the number of observed stars, $\bar{V}_{\rm s}$ and $m_{\bar{V}_{\rm s}}$ are the mean value of residuals and its accuracy.

4.3 The group corrections

With the results of PA II from Feb. 1992 to Mar. 1997, The group corrections of dt, d$\varphi$ and dz are computed by the chain method. The results are given in Table 3.

From Table 3, we can see that the closing error of dz is very small.

4.4 The frequency distributions of $\Delta\alpha$ and $\Delta\delta$

The frequency distribution of $\Delta\alpha$ and $\Delta\delta$ are given in Tables 4a and 4b respectively.

From Tables 4a and 4b, we can see that the position corrections for about $95\%$ of the FK5 stars are less than 20 ms in $\Delta\alpha$ or 0.30'' in $\Delta\delta$.

4.5 The systematic corrections

By the analytic method (Bien 1979; Working Group of GCPA 1983) and adopting the $\Delta\alpha$ and $\Delta\delta$ of FK5/FK4 Supp. stars obtained from the double transits, the systematic corrections of the catalogue of stars (CPASJ2-FK5) are analyzed. The systematic corrections on the right ascension and declination, $\Delta\alpha_\alpha$, $\Delta\delta_\alpha$, $\Delta\alpha_\delta$,$\Delta\delta_\delta$ are given in Tables 5a and 5b, respectively.

 

Table 1: The relation between residual and magnitude

 

 

Table 2: The relation between residual and spectral type

 

 

Table 3: The group corrections dt, d$\varphi$, and dz

 

 

Table 4a: The frequency distribution of $\Delta\alpha$

 

Table 4b: The frequency distribution of $\Delta\delta$

 

Table 5a: The systematic corrections (CPASJ2-FK5) $\Delta\alpha_\alpha$ and $\Delta\delta_\alpha$

 

Table 5b: