Assertion: asteroid | /r/CapableOf | use photoelectric photometers
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text: One very interesting and scientifically productive activity carried out by amateur astronomers over recent decades has been the attempt to establish the rotation periods of asteroids using photoelectric photometers and, in more recent years, CCD cameras.10 A lightcurve is constructed from the data, showing the asteroid's magnitude changing over time, and a rotation period is then deduced from it.11