Algorithm for IAU north poles and rotation parameters. Which way is up? (Q1311453)

We review the IAU definitions of north and of the location of prime meridian, and we present the algorithm which has been employed in determining the rotational parameters of the natural satellites. The IAU definition of the prime meridian contains some ambiguities which in practice have been `specified' by the numerical values published by the IAU working group but which have not yet been explicitly documented. The purpose of this paper is to explicitly document the algorithm employed by the IAU working group in specifying satellite poles and rotation rates.