2023JAVSO..51..159M

Time series images of the planetary nebula NGC 1501 were taken over several nights from the Las Cumbres Observatory robotic telescope network. Light curves of the central variable pre-white dwarf of NGC 1501, CH Cam, were derived using three different aperture photometry methods: image stacking on AstroImageJ, a custom Python program that used Source Extractor photometry, and a point spread photometry method. The light curves resulting from these photometric reductions were period-folded with multiple software routines including Skynet plotting, Astrosource, Period04, and Peranso. Approximately 30 prospective periods, ranging from 3 minutes to 110 minutes, were found. Some of these were similar to periods identified in previously-published literature, while others were not. Because CH Cam has been shown to have several pulsation modes, two pre-whitening methods–Period04 software and a custom Python sine-subtraction program–were also employed. Inconsistencies between periodograms resulting from the different photometric and analytic methods employed here, together with the low amplitude of the pulsations relative to the light of the background nebula and the expectation that these may vary with time, prevent us from drawing a firm conclusion about the pulsations of CH Cam.