A&A Supplement Ser., Vol. 124, July 1997, 189-196
Received August 22; accepted November 4, 1996
M. Odenkirchen - P. Brosche - F. Börngen - H. Meusinger - R. Ziener
Send offprint request: M. Odenkirchen
Sternwarte der Universität Bonn, Auf dem Hügel 71, D-53121 Bonn, Germany
Thüringer Landessternwarte Tautenburg, Sternwarte 5, D-07778 Tautenburg, Germany
We report on the measurement of absolute proper motions of
stars of magnitude 7 to 14.5 in a field in
the region of the M81 group of galaxies.
This work is part of the Bonn program for the extragalactic link
of Hipparcos. The proper motions were
determined from a collection of photographic plates covering the
time interval from 1894 to 1994. The absolute reference system
for the proper motions is represented by the galaxies M81, M82
and NGC3077, for which accurate optical reference positions
were obtained by means of an image cross-correlation technique.
For the majority of stars, the internal proper motion accuracy
is better than 1mas/a. The precision of the realization of the
absolute system is found to be around 1mas/a. In total, our
measurements yield absolute proper motions for 24 Hipparcos stars
and positions, proper motions and photometry for 330 additional stars
including a number of visual binaries and high proper motion stars.
Among the latter one G-type subdwarf is identified.
The results are relevant as a contribution to the Hipparcos link,
but also as a database for kinematic investigations.
keywords: galaxies: M81 -- astrometry -- reference systems -- catalogs