A three-color IR photometer suitable for speckle imaging or for traditional fast or slit-scan photometry is described, with special attention given to the photometer's scanning and relay optics, the dewar, the electronics, and the data acquisition and reduction hardware and software. The system is able to acquire sets of object and sky scans on three colors simultaneously, while concurrently performing a Knox-Thompson speckle analysis on the incoming data. The slit-scan photometry operation mode allows observations of objects too faint for speckle imaging. To date, the system was used to observe more than 20 T Tauri stars, several evolved stars, numerous binaries, and G29-38, with good agreement with published and known results for binary observations and those of NML Cyg and IRC + 10216.
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