Pulsational mode constraints for the rapidly oscillating Ap star HR 1217

High-speed photometric observations of HR 1217 have been obtained on four nights in 1983 December contemporaneously from the European Southern Observatory and from the South African Astronomical Observatory. A frequency analysis of three nights of data centred on the time of pulsation amplitude minimum yields the same two frequencies of highest amplitude found by Kurtz and Seeman (1983, Mon. Not. R. Astr. Soc., 205, 11) at pulsation amplitude maximum. A least-square fit of the six frequencies found by Kurtz and Seeman to the present data shows that the frequencies f3, f4 and f5 cannot be due to radial pulsation modes. It is suggested that f1 and f2 are associated with dipole pulsation modes and that f3, f4 and f5 are associated with quadrupole pulsation modes. (author)