Derived periods as a function of time. The derived periods listed in Table 2 based on matching CN image pairs are shown as filled blue circles, while periods based on the smooth phase cycles listed in Table 3 are given as filled orange squares. We estimate our uncertainties to be less than a few percent of the period, consistent with the small amount of scatter visible. Other published period determinations are shown with open symbols (see text for the various techniques employed). The dashed parabola is the fit to our 7 weeks of data, while the extrapolated curve (shown as dotted) simply continues the curve but must break down when the comet is further from the Sun and torques are reduced. Perihelion occurred on April 12 and is marked by the vertical dashed line.