With the announcement in 1978 (Kurtz, 1978) of short periodic photometric variations of HD 101065, the first member of a subgroup of CP2 stars was found. This gained attention due to the possibility of applying the methods of stellar seismology to late A to early F type stars. However, the extremely low photometric amplitude of these stars, which is typically few millimagnitudes in B, and the short periods, ranging from few minutes to about 15 minutes, make these stars difficult to discover and a considerable amount of telescope time is required to accumulate sufficient data for a reliable analysis of the frequency spectrum. As a consequence aliasing imposes serious problems. Synchronous observations from observatories well separated in longitude could overcome this dilemma, and have indeed proven to be sucessful (Kurtz and Seeman, 1983; Kurtz and Balona, 1984; Kurtz, Schneider and Weiss, 1985; Kurtz and Kreidl, 1985).