Determination of Nutation and Precession Based on Observations with the Pulkovo Polar Tube

Abstract

AbstractSince 1953 regular observations have been carried out with the polar photographic tube (PT) of A. A. Mikhailov at Pulkovo, a fixed astrograph (D = 200 cm, F = 600 cm) which can take photographs of a circumpolar zone of 60′radius. An analysis of measured polar distances of the same 30 stars on each plate gives corrections to the adopted values of coefficients of the nutation and precession constant. Though several papers have appeared during the last decade in which VLBI and LLR observations were used for the determination of the nutation coefficients and precession constant, the results from a 40-year series of observations with the PT are of interest, because of its two-times period of the principal nutation term. The method is fully independent.