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ACT Reference Catalog: Catalog Help


Overview

The ACT Reference Catalog is a positional and proper motion catalog of 988,758 stars covering the entire sky. The catalog was compiled by the U.S. Naval Observatory in order to provide more accurate proper motions for the stars in the Tycho Catalogue (ESA SP-100). To do this, positions from new reductions of the Astrometric Catalog (AC 2000) were combined with those from the Tycho Catalogue. The large epoch span between the two catalogs yields proper motions about an order of magnitude more accurate than those from the Tycho Catalogue alone. The data compiled in the ACT Reference Catalog include positions and proper motions in the Hipparcos System (J2000.0) for epoch J2000.0. Photometric data (B and V magnitudes) from the Tycho Catalogue are included.

For more information see the ACT Reference Catalog home page.


Parameters

act_id
The ACT catalog number of the star.

ra
The Right Ascension of the star at the requested epoch.

dec
The Declination of the star at the requested epoch.

magb
The B-band magnitude of the star (from Tycho Catalogue).

magv
The V-band magnitude of the star (from Tycho Catalogue).

type
Approximate spectral type of the star, calculated from the B and V colours.

Ux
The proper motion in right ascension, in milliarcsec/yr.

Uy
The proper motion in declination, in milliarcsec/yr.

arcsec
Distance from search centre in arcsec.


Reference

ESA, 1997, The Hipparcos and Tycho Catalogues, SP-1200

Roeser, S. and Hoeg E., 1993, The Tycho Reference Catalogue: A Catalogue of Positions and Proper Motions of One Million Stars, in Workshop on Databases for Galactic Structure, ed. A.G.D Philip, B. Hauck, and A.R. Upgren, L. Davis Press p. 137

Turon, C., Creze, M., Egret, D., et al., 1992, The Hipparcos Input Catalogue, ESA SP-1136

Urban, S.E., 1993, The U.S. Naval Observatory's Astrographic Catalogue Project, in Workshop on Databases for Galactic Structure, ed. A.G.D Philip, B. Hauck, and A.R. Upgren, L. Davis Press p. 145

Urban, S.E., 1997, New Reductions of the Astrographic Catalogue, in Proceedings of IAU Colloquium 165, ed. Wytrzyszczak, I.M., Lieske, J.H., and Feldman,R.A, Kluwer Academic Publishers, p. 493

Urban, S.E., Corbin, T.E., Wycoff, G.L., Martin, J.C., Jackson E.S., Zacharias, M.I., and Hall D.M., 1997, The AC 2000: The Astrographic Catalogue on the Hipparcos System, in preparation.

Urban, S.E., Corbin, T.E., and Wycoff, G.L., 1998, The ACT Reference Catalog, in press


 
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