Observations of the fortnightly nutation terms and the "dynamical variation of latitude" with photographic zenith tubes

Dennis D. McCarthy
1976 Astronomical Journal  
Observations made with three photographic zenith tubes show fortnightly nutation terms in good agreement with values determined from Earth tide observations. The radius of the circular "dynamical variation of latitude" occurring with the argument (a-2L) is found to be less than the rigid Earth values.
doi:10.1086/111909 fatcat:saiqfjp64vabbgy2mtiwc4lsua