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Paper: A synchronous motor chopper for laboratory testing of detector systems in infrared astronomy
Volume: 73, Airborne Astronomy Symposium on the Galactic Ecosystem: From Gas to Stars to Dust
Page: 579
Authors: Baltz, James A.; Erickson, Edwin F.
Abstract: Airborne and ground-based IR telescopes have oscillating secondary mirrors to permit subtraction of background emission from the sky and telescope. These chopping mirrors are synchronized to a clock which may originate in the data acquisition system. For laboratory testing of detecting instruments with such data systems, externally synchronized chopped IR sources are required. We describe a laboratory chopper in which a synchronous motor is driven by 2-phase sinusoidal currents in sync with an external clock at frequencies from 5 to 50 Hz. This design is used with the KAO's facility sources, the Chopped Hotplate and the Portable Chopped Light Source (PCLS).
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