Results on TYCHO photometry.
Snijders, M. A. J.; Grewing, M.; Evans, D. W.; Grenon, M.; Wagner, K.; Hog, E.; Halbwachs, J. L.; Wicenec, A.; Mauder, H.; Grossmann, V.; Baessgen, G.
Germany, United Kingdom, Switzerland, France, Denmark
Abstract
The final Tycho database will contain astrometric and photometric data for about 1 million stars. Here we discuss the results of the Tycho photometric calibration for about 80% of the data acquired by the star mapper of the Hipparcos satellite and estimate the photometric precision in the final Tycho photometric data base. For a non-variable star of 7th (10th) magnitude with =~100 observations a precision of better than 10mmag (40mmag) can be expected in the Tycho star catalogue. The precision on (B-V)_T_ depends only slightly on the colour and is expected to be better than 20mmag (60mmag) for the same number of observations. These results will be representative of the final Tycho photometric quality.