The proper motions of stars in the fields of 331 open clusters were taken from Four-Million Star Catalog (4M-catalog) of positions and proper motions (Volchkov et al. 1992). The proper motions included into this catalog have been derived as the coordinate differences between Guide Star Catalog of the Hubble Space telescope and the computer-readable version of the Astrographic Catalog, also known as the Carte du Ciel catalog (Kuimov et al. 1992), and reduced to PPM system of proper motions.

The mean absolute proper motions of open clusters were computed by averaging the 4M-catalog proper motions of their members selected on the basis of the photometric color-magnitude diagrams, radial velocities, and the membership probabilities by relative proper motions. These data have been taken from the database by J.-C. Mermilliod (1988, 1992).

The absolute proper motions for 21 young open clusters have been derived by comparison of precise relative proper motions of individual stars and their corresponding absolute proper motions. The RMS deviation of these differences is estimated as 0.003 - 0.004 arcsec/yr (Glushkova et al., 1996). It can be treated as crude estimate of 4M catalog accuracy.

To reduce 4M system of proper motions to HIPPARCOS system, we used new catalog of absolute proper motions derived by A.A.Volchkov. It contains approximately 800000 stars. As for 4M catalog, their proper motions were calculated from coordinate differences between TYCHO and Carte du Ciel positions and then reduced to HIPPARCOS system. We used common stars of TYCHO program and 4M catalog in the fields 2 x 2 degrees (3 x 3 in some cases) centered in open clusters and calculated median differences of their proper motions, found in TYCHO and 4M catalogs. Mean number of stars in 2 x 2 field changed from 100 to 400.

This data set is the computer-readable version of the tables published in Pis'ma Astron. Zh. (Glushkova et al. 1996, 1997, 1998; Volchkov et al. 1998) and is available from Sternberg Astronomical Institute via anonymous ftp: ftp.sai.msu.su/pub/groups/cluster/cl/pm/meanpm.txt

All clusters in the present data set are arranged in the order of their names. Galactic coordinates are taken from the Lynga catalog (1987).

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meanpm.dat 22 KB

Note on Cluster name:

cluster CARINA includes the open clusters TR14, TR16 and CR232

Note on rms errors in RA and Dec proper motion.

Rms error equals to 99 when the absolute proper motion was derived by 1 or 2 members of the cluster.

Glushkova E.V., Zabolotskikh M.V., Rastorguev A.S., Uglova I.M., and Fedorova A.A. "Determination of absolute proper motions of stars in 21 open cluster". 1996, Pis'ma Astron. Zh. 22, 850 (Astronomy Letters. 1996, Vol.22, No.6, P.764)

Glushkova E.V., Zabolotskikh M.V., Rastorguev A.S., Uglova I.M., Fedorova A.A. "Absolute proper motions of 181 young open clusters". 1997, Pis'ma Astron. Zh. 23, 90 (Astronomy Letters. 1997, Vol.23, No.1, P.71 )

Glushkova E.V., Zabolotskikh M.V., Rastorguev A.S., Uglova I.M., Fedorova A.A., Volchkov A.A. "Absolute proper motions of 98 old open clusters". 1998, (in preparation).

Kuimov K.V., 1992, in: O Chetyrekhmillionnom Kataloge Zvezd (On the Four-Million Star Catalog), eds. Gulyaev A.P., Nesterov V.V., Izd.MGU, Moscow, p.27

Lynga G. 1987, The cataloge of open clusters, 5 ed., 1987 , computer- readable version

Mermilliod J.-C., 1988, Bull.Inform.CDS., no.35, 77

Mermilliod J.-C., 1992, Bull.Inform.CDS., no.40, 115

Volchkov A.A., Kuz'min A.V., Nesterov V.V., 1992, in: O Chetyrekhmillionnom Kataloge Zvezd (On the Four-Million Star Catalog), eds. Gulyaev A.P., Nesterov V.V., Izd.MGU, Moscow, p.67

Volchkov A.A. et al "The corrections to the absolute proper motions of 202 open clusters". 1998, in preparation