On the Feasibility of a Star Coordinate Determination in the Radio Astrometry Reference System [chapter]

V. S. Gubanov
1986 Astrometric Techniques  
At present it is evident that the stability of a cglestial coordinates system with an accuracy of at least 0.01 per century, with respect to an internal frame can be derived only from VLBI observations of compact extragalactic radio sources. At the same time it is expected that the need for improved stars 1 coordinates will be strongly felt at least up to the end of this century, because stars are important and more convenient observational objects then very weak extragalactic sources or
more » ... c sources or artificial Earth satellites (AES). One therefore wonders if oxie can use the high precision and stability of the radio astrometric reference frame to stabilize and improve the reference frame given by star catalogues* The problem of the relationship between these systems has so far been investigated in the form of determining the parameters of their mutual orient ation, and/or studying systematic errors of star catalogues (Gubanov, 1978; Kumkova, 1978, 1981)* This problem has been attacked by direct photography of several optically identified radio sources or VLBI observations of few radio stars. The present paper shows the feasibility of determining the place of any star of sufficient magnitude with reference to the radio astrometric frame, as given by extragalactic source positions (Gubanov, 1983)* This is done by introducing an AES, equipped with radio signal for VLBI observations and a corner reflector for laser ranging, which can be observed by radio methods as well as optically (Gubanov, 1976)* This satellite should also be bright enough in the reflected sun f s light to be observed in the star field with a precision photoelectric satellite camera* Consider a three element VLBI complex (A-j, A2, A3), which regularly observed an extragalactic source with known coordinates with respect to the radio astrometric reference frame* One such observation on the base of A-|A 2 yields a condition equation of the form: 765 H. K. Eichhorn and R.J. Leacock (eds.), Astrometric Techniques, 765-771. ©1986 by the IAU. available at https://www.cambridge.org/core/terms. https://doi.
doi:10.1007/978-94-009-4676-7_96 fatcat:cije5r6l3vg3fnrnfyt7oixara