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Up: The Potsdam contribution

6. Discussion of the results

 

All determinations of the spin parameters were carried out by the use of H37cr data. In order to express our results in the final Hipparcos system, we compared them with the composed solution of Kovalevsky et al. (1997) based on different programmes and techniques. In this synthesised solution the Potsdam star solution with 256 stars was included.

The residual spin parameters of the Potsdam solution in the final Hipparcos system were obtained by subtracting the composed solution of Kovalevsky et al. (1997)

tex2html_wrap_inline1228 [mas/yr]

from the Potsdam solution with H37cr. All residual spin parameters tex2html_wrap_inline1230 of the final Potsdam solution are smaller than their errors. Table 3 from Kovalevsky et al. (1997) shows the residual spin parameters for the different programmes used in the synthesised solution. The high quality of the Potsdam contribution is underlined by its increased weight in the process of the synthesised solution by Kovalevsky et al. (1997) and the relatively small deviation from the VLBI data. From the comparison with the results presented in Kovalevsky et al. (1997) we may conclude that the small internal errors of the Potsdam spin parameters (tex2html_wrap_inline1232 0.5 mas/yr) correspond to the real errors.

Acknowledgements

We would like to thank the Karl-Schwarzschild-Observatorium of the Thüringer Landessternwarte Tautenburg for supplying the large number of Schmidt plates used for this project. Furthermore, we are grateful for extensive support with the measurements on the APM (IoA, Cambridge), MAMA (Observatoire de Paris), PDS (University Münster), PARSEK (Main Astronomical Observatory of Ukrainian Academy of Sciences, Kiev) and ASCORECORD (Technical University Dresden) measuring machines. We thank H.-J. Tucholke for providing his results in the field of 3C345 for this work.



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