plural -s

Definition of coelostat

: an instrument consisting of an adjustable plane mirror clock-driven on an axis parallel to the axis of the earth and a second fixed mirror that act together to send light from a celestial body in a fixed direction — compare heliostat

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History and Etymology for coelostat

International Scientific Vocabulary coelo- (from Medieval Latin caelum sky, heaven, from Latin caelum heaven) + -stat

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