| 摘要 |
PURPOSE:To maintain an image of which variation in focal point position due to variation in temperature is corrected without driving the optical system, in the optical system of a radiometer which is mounted on an artificial satellite and measures an incident light from the earth. CONSTITUTION:An incident light 1 to a lens 2 or an optical system with the same effect as the lens passes through an optical path split element 4, and focuses on a line sensor 3a. Usually, the temperature of the optical system varies, and the incident light 1 passes through the optical path split element 4 and focuses on either of line sensors 3b and 3c placed at different focal distances from each other, to maintain an image of which focal point displacement is corrected. |
