The FK5 equinox and equator from combined radar and optical data of the near-earth asteroids

TL;DR: In this article, an analysis of the differences between the Hipparcos and FK5 catalogues is presented, with two main objectives: first, to determine whether or not there is a pure rotation between the two catalogues, and second, to decide which model best represents the residuals.

TL;DR: Radar is a powerful technique that has furnished otherwise unavailable information about solar system bodies for three decades as mentioned in this paper, and the advantages of radar in planetary astronomy result from (1) the observer's control of all the attributes of the coherent signal used to illuminate the target, especially the wave form's time/frequency modulation and polarization; (2) the ability of radar to resolve objects spatially via measurements of the distribution of echo power in time delay and Doppler frequency; (3) the pronounced degree to which delay-Doppler measurements constrain orbits and spin vectors;