Main Astronomical Observatory, Russian Academy of Sciences, Pulkovo,
Pulkovskoye Shosse 65/1, St.-Petersburg, 196140, Russia
E-mail: vitnaumov@gaoran.spb.su
The traditional methods of determination of corrections to nutation coefficients and precession constant are still useful in spite of rapid development of modern techniques. In this connection the results from 40-year series of observations with the polar tube at Pulkovo -- the telescope, that have been built specially for the determination of nutation and precession constants, are of interest. The correction to the principal nutation term in obliquity was derived as a result of reduction of observational data of 1953--1993. The possibility of the determination of precession constant on the bases of the same data is discussed.