Top: raw photometry computed by summing the background-subtracted counts inside a circular aperture (3 pixel radius) centered on K2-24. Bottom: photometry after correcting for variations due to telescope roll angle. Noise on three-hour timescales has been reduced by a factor of 8. The ∼0.1% variability gives an upper limit to intrinsic stellar variability. Visual inspection gives a weak suggestion of a ∼20-day periodicity, but we do not consider this a compelling detection of rotational modulation. Since stars drift perpendicular to the roll direction over the course of a campaign, it is difficult to disentangle long-term astrophysical variability from position-dependent variability. The data used to produce the bottom panel is included as an electronic supplement.The data used to create this figure are available.