The Tycho Catalog compiles
observations by the star mapper on board the ESA Hipparcos
satellite. The catalog provides astrometry (positions, parallaxes and
proper motions) and two-colour photometry in B and V, for for than one
million stars brighter than V=11.5 mag. The median precision (standard
error) is 25 mas in position, and 0.10 mag in the B-V colour
index. These values apply at the median magnitude V=10.5 for stars of
median colour index B-V~0.7. The precision is greater for brighter
stars, with typical errors of 7 mas in position and 0.019 mag in B-V
for stars brighter than V=9 mag.
For more information, see the Hipparcos home page.
The Tycho-2 catalog number of the star.
The Right Ascension of the star at the requested epoch.
The Declination of the star at the requested epoch.
The B-band magnitude of the star.
The V-band magnitude of the star.
An approximate spectral type for the star, calculated from the B-V colour.
The proper motion in right ascension, in milliarcsec/yr.
The proper motion in declination, in milliarcsec/yr.
Distance from search centre in arcsec.
Hog, E. et al., 2000, Construction and verification of the Tycho-2
Catalogue, A&A, 357, 367.