Charge coupled device based phase resolved stroboscopic photometry of pulsars

A stroboscope designed to observe pulsars in the optical spectrum is presented. The absolute phase of the stroboscope is synchronized to better than 2.5 μs with the known radio ephemerides for a given pulsar. The absolute timing is provided by the Global Positioning System clock. With such a device resolved photometry of pulsars can be performed. We demonstrated the instrument’s capabilities with the results of a set of observations of the Crab pulsar, the brightest of the known optical pulsars, with a visual magnitude of 16.5, and a rotational frequency of ∼29 Hz.