| 摘要 |
PROBLEM TO BE SOLVED: To provide a mirror protecting dome free from the distortion of an image in picking up the image reflected by a mirror. SOLUTION: The protective dome 24 is a member for protecting a hyperboloidal mirror 22 so that a foreign matter may not intrude in an optical path between the hyperboloidal mirror 22 and a camera 26. The protective dome 72 has spherical shape, in a range where the angle of depression is≥2°within the range of the angle of depression seen from the focus 34 of the hyperboloidal mirror 22, and has conical shape in a range, where the angle of depression is <2°within the range of the angle of depression seen from the focus 34 and in the range of the angle of elevation. The protective dome 72 has circular-arc shape, in the range where the angle of depression is≥2°within the range of the angle of depression, as seen from the focus 34 of the hyperboloidal mirror 22, considering the cross section of the hyperboloidal mirror 22 in an axial direction as shown by the Figure, and has linear shape in the range where the angle of depression is≤2°within the range of the angle of depression seen from the focus 34 and in the range of the angle of elevation. COPYRIGHT: (C)2006,JPO&NCIPI
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