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The Hipparcos Input Catalogue has been compiled, over the period 1982-1991, as the definitive observing catalogue for the European Space Agency’s Hipparcos satellite, launched on 8 August 1989. It contains the most up-to-date, comprehensive and homogeneous information on the 118 000 stars being observed by Hipparcos. Its stellar and data content is(More)
The orbital elements of 11 spectroscopic binaries with brown dwarf candidates (M2 sin i between 0.01 and 0.08 M⊙) are combined with the Hipparcos observations in order to derive astrometric orbits. Estimations of the masses of the secondary components are thus calculated. It appears that 5 secondary masses are more than 2σM2 above the limit of 0.08 M⊙, and(More)
The Gaia mission is designed as a Galaxy explorer, and will measure simultaneously, in a survey mode, the five or six phase space parameters of all stars brighter than 20th magnitude, as well as providing a description of their astrophysical characteristics. These measurements are obtained by combining an astrometric instrument with micro-arcsecond(More)
This contribution is intended as a ‘rough guide’ to the Hipparcos Catalogue for the non-expert user. Some general aspects of the use of astrometric data are discussed as well as Hipparcos-specific applications. We discuss when and at what level one may expect systematic errors to occur in the Hipparcos Catalogue. Next we discuss the question of the(More)
The distribution of interstellar extinction has been mapped over the whole sky, using all available spectral and photometric data. The colour excess distribution is modelled as a function of galactic latitude, longitude and distance within about 1 kpc from the Sun. The model was used to predict the reddened Tycho and Johnson (B − V ) colours, with the(More)
Serendipitous stellar occultation technique provides a powerful and unique tool to probe the outer Solar system matter, e.g. Kuiper disc and Oort cloud. We present the results of a serendipitous occultation observation campaign carried out with ULTRACAM, mounted on the ESO-VLT telescope, during 2005 May 17–20. The data are processed using the variability(More)