Comparison of Frequency Determinations of Slowly Pulsating B Stars from Stromgren and Geneva Data

Slowly Pulsating B Stars have been on the observing program of the Four College Consortium Automatic Photometric Telescope (FCAPT) since shortly after its commissioning in 1989. The Mercator telescope in the Canary Islands has also observed many of the same stars. Since these telescopes are separated by approximately 6 hours of longitude there is little overlap in the time of observation of any target. Also the APT observations are obtained with Stromgren filters while the Mercator observations are with the Geneva filters. Since neither the time of observation, the filter set, or the telescopes are the same we feel that frequency determinations from the two data sets should be essentially independent. Thus the occurrence of the same frequency in both data sets should be a good indication of its reality. In this paper we compare the frequency spectra of three of these strs (HD1976, HD25558, and HD222555). Such a comparison allows us to verify the strongest frequencies of each star as well as some of the weaker terms. We have also attempted to combine our Stromgren u filter measures with Geneva U filter measures. We have found that the result of using the combined data sets aids in deciding between one cycle per day aliases.