The authors investigate the motion of a test particle in the Kerr metric using Boyer-Lindquist coordinates, extending the results of de Felice and Calvani (FC) (1972) to cases not covered by them, and also considering further details concerning, in particular, photons moving along the principal null congruences. Whereas FC considered only nonnegative values of L = q + l-squared, here negative values are treated. Curves are drawn showing l-aquared as a function of Theta for a fixed positive Gamma and typical values of L, demonstrating the oscillatory nature of the latitudinal motion. Four families of photon world lines with constant latitudes are found. A graph of L/a-squared versus x for a fixed l/a is drawn from calculations, which is used to analyze the r-motions of photons.
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