Wide field telescope for photographing earth from space - has fixed concave mirror as objective and mobile convex mirror

摘要

The wide field telescope has a fixed objective comprising a spherical concave mirror (10), a mobile convex mirror (14) pivoted about the centre of curvature of the objective, and a receiver placed at the focus of the system. Two plane mirrors (22,24) are placed between the receiver (18) and the convex mirror (4). These three mirrors form a unit which may be pivoted about the fixed axis joining the centre of curvature of the objective to the centre of the receiver. The mobile axis joining the centre of curvature of the objective to the centre of the convex mirror makes an angle of about 14 deg. with this fixed axis. The telescope may be used for photographing the earth from satellites.