The astronomical literature contains many papers about possible low amplitude photometric variability of the upper main sequence non-magnetic chemically peculiar stars: the metallic-line (Am) and the Mercury-Manganese (HgMn) stars. It is important either to confirm or to set limits on such claims as the results are crucial to our understanding these stars. This paper examines differential Strömgren uvby photometry obtained during the first six years (Sept. 1990 - July 1996) (year 1 is Sept. 1990-July 1991, year 2 is Sept. 1991 - July 1992, etc.) of the 0.75-m Four College Automated Photoelectric Telescope (FCAPT) on Mt. Hopkins, AZ. The telescope measured the dark count and then in each filter the sky-ch-c-v-c-v-c-v-c-ch-sky where sky is a reading of the sky, ch that of the check star, c that of the comparison star, and v that of the variable star. By measuring two non-variable stars for each potentially variable star, one can derive an estimate of the accuracy of the photometry. This paper extends previous results for 53 Tau, 68 Tau, HR 4072, and HR 6096 (Adelman 1993) as well as examines observations of 15 Vul and o Peg obtained this past observing year.
Table 1 (click here) gives information on each group of variable, comparison, and check stars (Hoffleit 1982). Tables 2-7 contain the new observations along with the yearly and total means and standard deviations. No corrections have been made for neutral density filter differences among each group of variable, comparison, and check stars.
