3 Results

The results are given in Table 1, only available in electronic form at the Centre de Données Astronomiques de Strasbourg (CDS). The content of the columns is:

Column 1: LTT number.
Column 2: Location number. The first two digits give our area number, and the remaining digits our star number.
Column 3: LTT photographic magnitude.
Columns 4 and 5: RA and Dec for J2000.0.
Column 6: Total annual proper motion for J2000.0.
Column 7: Total annual proper motion error.
Column 8: Position angle for J2000.0.
Column 9: Difference (Dpm) between our proper motion and that given by Luyten, in the sense LTT-W&C.
Column 10: Difference (Dpa) between our position angle and that given by Luyten, in the sense LTT-W&C.
Column 11: Remarks(Re).

Both the total annual proper motions and the position angles given in Table 1 are the average of two independent determinations, based on different first/second epoch plate pairs. Eight stars that are common to two overlapping areas have been identified with an (*) in the Remarks column. The results given for them are therefore average values based on four first/second epoch pairs. The standard deviation of these latter averages provide the means to independently ascertain the errors of the positions and proper motions. The computed Sigmas varied between: 0.13 $\hbox{$^{\prime\prime}$ }$ and 0.26 $\hbox{$^{\prime\prime}$ }$ (positions), and between 0.010 and 0.030 arcsec/year (proper motions). Keeping in mind that these Sigmas are based on only four independent measures, it is interesting to note that they are consistent with the error estimates given in Table 1 for the proper motions, and also with the presumed errors of the positions quoted in Sect. 2.

As shown by Figs. 1 and 2, which are plots of the residuals Dpm and Dpa as a function of the coordinates, the is no clear evidence of systematic differences between our values of the proper motions and position angles and those given by Luyten. Highly discordant cases (see next section) were not included in the plots.

Figure 2: a-b) Differences in the sense LTT-W&C between our position angles and those of Luyten, plotted as a function of the coordinates

Finding charts for stars fainter than magnitude (LTT) $\sim 10$ (136 objects) are presented in Fig. 3. They will appear only in the on-line edition of the journal. The charts were reproduced from digitized images extracted from the Digitized Sky Survey (DSS), produced by the Space Telescope Science Institute (STScI). Charts are 4.5 arcmin on a side. North is at the top, East to the left.