Hipparcos homepage http://astro.estec.esa.nl/SA-general/Projects/Hipparcos/hipparcos.html
The Hipparcos Catalogue (118 218 entries) and the Tycho Catalogue (1 058 332 entries) - the two catalogues resulting from the Hipparcos space astrometry mission - were both declared final on 8 August 1996, 3 years after the end of satellite operations. This completion date was, to within a month, that targetted for the Hipparcos Catalogue pre-launch, and 1 year in advance of the completion date targetted pre-launch for the Tycho Catalogue.
The astrometric and photometric results completely surpass all of the original mission objectives. For the Hipparcos Catalogue, median astrometric accuracies are around 1 milliarcsec; 10% of the objects have accuracies better than about 0.5 milliarcsec; 49 399 of the 118 218 objects have distances determined to better than 20%. 11 597 Hipparcos Catalogue entries are categorised as variable (8237 being newly-identified as variable), with 23 882 systems solved or suspected as double or multiple. In addition, the Hipparcos and Tycho Catalogues provide global photometric results of unprecedented quantity, accuracy and homogeneity.
All of the scientific aspects of this highly complex mission have been coordinated by the Project Scientist in ESTEC who has, in addition to taking responsibility for all the Project Scientist activities since the mission's acceptance in 1980, led the activities of the catalogue completion, documentation and distribution of final mission data to the PIs. The Project Scientist was responsible for coordinating the overall catalogue validation, and the preparation of the mission products for publication - in both printed form and on a set of CD-ROMs. It should also be recalled that the Project Scientist took on the role of project manager during the satellite's operational phase.
The total set of mission products - documentation, catalogues, annexes on double and variable stars, identification charts, variable star light curves, and CD-ROMs for both the Hipparcos and Tycho Catalogues will be released by ESA on 1 June 1997. Three volumes of the final 16-volume set have been prepared in collaboration with Sky Publishing Corporation, who are basing their Millennium Atlas exclusively on data from the Hipparcos mission, and are collaborating with ESA on this celestial map.
The policy of fully defining and documenting the final catalogues before release has generally been understood and appreciated by the community. Nevertheless, the Hipparcos project has responded swiftly to requests for time-critical data, supplying high quality calibration and guide star data for ISO operations, positional data for the Galileo encounter with asteroids Gaspra and Ida and for the Comet Shoemaker-Levy 9 impact with Jupiter.
Despatch of Hipparcos data to PIs began in early August 1996 (following the catalogue completion) and will remain available to the PIs during the 10-month proprietary period (August 1996 - June 1997) during the preparation of the data for publication. Data concerning a total of 700 000 objects related to almost 200 proposals were dispatched to PIs by the Hipparcos Project, accompanied by the draft catalogue documentation manual. This large and complex data distribution exercise proceeded smoothly, and no negative reactions concerning either the data transfer or data contents were received from PIs. The first scientific papers using the Hipparcos and Tycho data are expected to start appearing in the literature shortly.
Figure 3.2.2/1: The Hertzsprung-Russell diagram for nearby
stars, adapted from Fig. 6 of Perryman et al., 1995 (A&A,
304, 69), showing the results of the data obtained from the 30-
month solution, retaining distances accurate to 10%, except for
the red giant branch, where objects with accuracies of 20% have
been included. The figure includes 10 793 objects, and completely
supersedes all previous attempts at determining the structure of
the HR diagram for stars in the solar neighbourhood.
Data distribution to the second wave of PIs those of the '1982 proposals' - took place at the end of 1996, consistent with the relative release schedule committed to throughout the mission.
The general catalogue release was preceeded by the scientific symposium Hipparcos Venice '97, held on Isola di S. Giorgio, Venice, 13-16 May 1997, organised by the Project Scientist and P.L. Bernacca with the support of the Hipparcos Science Team.
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