منابع مشابه
The Future of Space Astrometry
The future of space-based astrometric missions appears to be very promising. Three missions were described at IAU Colloquium 180. These are the Full-sky Astrometric Mapping Explorer (FAME), the Space Interferometry Mission (SIM) and the Global Astrometric Interferometer for Astrophysics (GAIA) missions. These missions will substantially improve the accuracy of global astrometric measurements ma...
متن کاملSpace - VLBI phase - reference mapping and astrometry
We present 5 GHz space-VLBI observations of the quasar pair B 1342+662 / B 1342+663 that demonstrate the feasibility of phase-reference techniques using an antenna in space. The space-based data were taken by the satellite HALCA, of the space-VLBI mission VSOP. From residual (referenced) phases we derive an upper bound of 10 meters to the uncertainty of the spacecraft orbit reconstruction. An a...
متن کاملModelling of a Space-based Ronchi Ruling High-precision Astrometry
An end-to-end rnodelling program for an astrometric telescope employing a Ronclli ruling has been developed. The program models the aberrated images formed anywhere in the field-of-view. It then determines apparent centroids by simulating the motion of a Ronchi ruling across the field. Photo-electran statistic+ are included. A 6 term plate-constant model is used to determine the apparent motion...
متن کاملObervational Model for Microarcsecond Astrometry with the Space Interferometry Mission
The Space Interferometry Mission (SIM) is a space-based long-baseline optical interferometer for precision astrometry. One of the primary objectives of the SIM instrument is to accurately determine the directions to a grid of stars, together with their proper motions and parallaxes, improving a priori knowledge by nearly three orders of magnitude. The basic astrometric observable of the instrum...
متن کاملObservational Model for Precision Astrometry with the Space Interferometry Mission
The basic astrometric observable of the Space Interferometry Mission (SIM) instrument is the pathlength delay. This measurement is made by a combination of internal metrology measurements that determine the distance the starlight travels through the two arms of the interferometer and a measurement of the white light stellar fringe to nd the point of equal pathlength. Because this operation requ...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1974
ISSN: 0074-1809
DOI: 10.1017/s0074180900069977