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Double star CCD astrometry and photometry
Irwin, M. J.; Argue, A. N.; Lampens, P.
About 3000 CCD measurements of double stars have been made in one or both filters V and R on the 1m Jacobus Kapteyn Telescope at La Palma. The stars form part of the INput CAtalogue (INCA) of the astrometric satellite HIPPARCOS, and require both astrometry and photometry in order to facilitate reduction of the HIPPARCOS measurements. The primary c…
Améliorations des positions des etoiles Hipparcos par l'utilisation des observations ``star-mapper''
Mignard, F.; Donati, F.; Falin, J. L. +2 more
Results on star-mapper data for attitude determination based on observations carried out over fifteen reference great circle's (RGC) are presented and discussed. Precision on the three-angle attitude reconstruction is of the order of 60 milli-arcsec along-scan and 100 and 180 milli-arcsec normal-to-scan. With this first year data, it is possible t…
Infrared and radio astronomy, and astrometry. Proceedings. Symposia 7, 8 and Topical Meeting of the COSPAR Interdisciplinary Scientific Commission E (Meeting E5) of the COSPAR 28. Plenary Meeting: Infrared and radio astronomy, and astrometry, The Hague (Netherlands), 25 Jun - 6 Jul 1990.
Perryman, M. A. C.; Smoot, G. F.; Wesselius, P. R. +2 more
Contents: 1. Astrometry from space (Symposium 7). 2. The infrared and submillimeter universe at high redshift (Symposium 8). 3. Space VLBI (Meeting E5).
Hipparcos: First results of the photometric processing
Mignard, F.; Grenon, M.; Falin, J. L. +1 more
The analysis of the photon counts collected by the ESA HIPPARCOS satellite allows to determine for each program star a magnitude in the H-filter. We present the general principles of the data reduction restricted to the photometry. It is shown that photometric recognition of close binary stars, down to 100 arcsec separation is an attainable goal, …
Luminosity of large amplitude variable stars: Comparison between ground-based predictions and observations by the Hipparcos satellite
Barthes, D.; Mennessier, M. O.; Davies, P.
Since November 1989, the HIPPARCOS satellite has been observing stars in order to fulfil its mission goals. The complete data processing of these observations will take many years to perform. A small group of stars, namely the large amplitude variables, must be processed much closer to real-time so that the luminosity ephemeris can be updated wher…
Cometary ion distributions near the pickup energy outside comet Halley's bow shock
Coates, A. J.; Neugebauer, M.; Gombosi, T. I. +2 more
This paper compares calculated and measured energy spectra of implanted H+ and O+ ions on the assumption that the pick-up geometry is quasi-parallel and about 1% of the waves generated by the cometary pickup process propagates backward (towards the comet). The model provides a good description of the implanted O+ a…