Adelman et al. (1994) presented differential uvby photometry of the mCP ultra-sharp lined star HR 8216 (= HD 204411) obtained between 1990 and 1994. The data for the three observing seasons with many observations showed that this star was constant and values in the literature indicate that this has been the case for many additional years. Its constancy has been confirmed also by Hipparcos photometry (ESA 1997). Any evidence of variability can lead to an estimate of its rotational period. Table 5 summarizes the FCAPT photometry. For three of the eight observing seasons, there are only a few observations and differences in ch-c values between these and other years are probably due to their poorer statistics. The 1996-97 and 1997-98 seasons have sufficient observations to clearly show that HR 8216 was constant (Table 6). The telescope being moved just before the start of observing in the fall of 1996 and the order 0.01 mag changes in ch-c values seen between the last two and first 6 observing seasons might simply reflect small errors in the extinction. The offset seen in the ch-c values of b is currently unexplained. Comparison of the v-c values for
1991-94 vs. 1996-97 show small offsets in u, v, b, and y, respectively of 0.004, 0.000, 0.007, and 0.004 mag. Although these differences are suggestive of possible long term variability, observations in additional years are needed for confirmation.
This work was supported in part by NSF grants AST-9115114 and 9528506 and in part by grants from The Citadel Development Foundation. We appreciate the continuing efforts of Louis J. Boyd, Robert J., Dukes Jr., and George P. McCook to keep the FCAPT operating properly.
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