  We investigate the RR Lyrae population in NGC 147, a dwarf satellite galaxy
of M31 (Andromeda). We used both Thuan-Gunn g-band ground-based photometry from
the literature and Hubble Space Telescope Wide Field Planetary Camera 2
archival data in the F555W and F814W passbands to investigate the pulsation
properties of RR Lyrae variable candidates in NGC 147. These datasets represent
the two extreme cases often found in RR Lyrae studies with respect to the phase
coverage of the observations and the quality of the photometric measurements.
Extensive artificial variable star tests for both cases were performed. We
conclude that neither dataset is sufficient to confidently determine the
pulsation properties of the NGC 147 RR Lyraes. Thus, while we can assert that
NGC 147 contains RR Lyrae variables, and therefore a population older than ~10
Gyr, it is not possible at this time to use the pulsation properties of these
RR Lyraes to study other aspects of this old population. Our results provide a
good reference for gauging the completeness of RR Lyrae variable detection in
future studies.
