The relationship between mean anomaly block sizes and spherical harmonic representations


  • Richard H. Rapp


The often used rule specifying the relationship between a mean anomaly in a block whose side length is θ° and a spherical harmonic representation of those data to degree math formula (i.e. θ° math formula = 180°) is examined by considering the smoothing parameter used by Pellinen [1966]. We have found that mean anomalies computed from potential coefficients without considering the smoothing parameter can be in error by about 30% of the root-mean-square anomaly value. In addition, tests with actual 5° mean anomaly data show that there is considerable gravity information above degree 36 in these anomalies. We conclude that the above mentioned rule should be considered only a crude approximation.