coelostat

英 ['siːləstæt] 美 ['sɪləˌstæt]

• n. [天]定天镜( 观测或拍摄天体时镜面与地轴一同转动可使图像固定不动)

英英释义

Noun:

1. optical device used to follow the path of a celestial body and reflect its light into a telescope; has a movable and a fixed mirror