Fast variations of the solar rotation

The rotation law of the Sun is often described by the Faye formula: xi(phi) =a-b sin2 phi, where phi is a heliographic latitude and a and b are constants. For a long time researchers have been studying the problem in what way the constants a and b change in time and in dependence on a phase of 11-year cycles. The results of solar rotation observations in cycle No. 19(1955-1963) and No.20 (1965-1973) are presented in this report. (Auth.)