\documentstyle{article}
%\global\numpagefalse
%\heading{FK5 Catalogue corrections from.,}{SHUYGINA,N.V., YAGUDINA,E.I}
\title{ FK5 Catalogue corrections from \\
        combined radar and optical data\\
        of near-Earth asteroids          }

\author{N.V.Shuygina, E.I.Yagudina \\ 
Institute of Applied Astronomy, Russian Academy of Science\\
         Zhdanovskaya str., 8, St.Petersburg 197042, Russia}
%\Email{MVV}{IPA}{RSSI.RU}

\begin{document}
\maketitle
\begin{abstract}

      The usage of combined radar and optical observations of several 
near-Earth asteroids (NEAs) - (1862) Apollo, (4179) Toutatis, (1620) 
Geographos, (3908) 1980 PA, (4769) 1989 PB and unnumbered 1990 MF - in
order to determine the equinox and equator of a celestial reference frame 
showed us that these data can be successfully applied to solve the problem. 
It is well known that even few radar measurements, when added to optical 
ones, significantly improve asteroid's ephemerides and reduce errors of 
corrections to the orbital elements. Orbit determination process for each 
minor planet was made on the basis of both optical and radar measurements. 
The analysis of optical residuals for all asteroids mentioned above 
was fulfiled to estimate corrections to the catalogue equinox and its 
secular variation. It was obtained the preliminary value (0.305$''$ $\pm$ 
0.047$''$) of the FK5 equinox correction, its secular variation (-0.3$''$/cy 
$\pm$ 0.3$''$/cy), and (0.086$''$ $\pm$ 0.044$''$) as the FK5
equator. Results of zero-point corrections determination were proved 
to be more reliable with radar data involved.

     The simulation was also completed for obtaining an influence of a 
number and properties of NEAs on the process of determination the equinox 
and equator corrections. Recomendations for the choice of asteroids to be 
included in this investigation are formulated. 

\end{abstract}
\end {document}
