coelostat

coelostat (SEE-loh-stat) - n., an astronomic device with an adjustable mirror driven by a clock that can track a celestial body and reflect its light into a fixed instrument.


Most ground-based solar telescopes (formerly called heliostats) are coelostats. Coined from Latin coelestis, sky, alteration of caelestis/caelum, sky/heavens + -stat, root meaning an instrument or agent that keeps something (specified) stable or stationary, from Greek statis, that which stops or makes steady.

---L.