Period Changes in SX Phoenicis Stars: IV. BL Camelopardali

A total of 73 new times of maximum light for BL Cam were observed through the years 2005-2011, which are combined with 1392 times of maxima taken from literature. A more accurate period of 0.039097912(1) days was found, and an updated linear ephemeris is presented. This newly presented linear ephemeris was used to calculate revised O - C values, which were fitted with a parabolic curve to measure the rate of change of the pulsation period, found to be (1/P)(dP/dt) = 1.37(2) × 10^-7 yr^-1. Although the parabolic fit has a physical interpretation, it is noted that a cubic more appropriately fits the behavior of the O - C diagram.