GPol, Gemini Polarization Units, are facilities that make polarimetric observations possible on both Gemini (link opens in a new window) telescopes. They operate over the optical-infrared wavelength range from 0.3 to 5 microns. Detecting the polarisation of light from astronomical objects provides information about local magnetic fields, or the location of objects such as newly born stars that are shrouded in clouds of gas and dust.
GPol consists of a set of three deployable trays, each of which has a motor-driven turntable to permit rotation of the polarising wave plate to various position angles on the sky.
GPol is used in combination with other Gemini Instruments such as NIRI, the Near-Infra Red Imager, and GMOS, the optical imager/spectrometer.
GPol North was shipped to Gemini North in Hawaii in February 2002; GPol South was shipped to Gemini South in Chile in July 2002.