GB1099026A - Stabilized optical systems - Google Patents

Abstract

1,099,026. Stabilized optical systems. BELL & HOWELL CO. March 30, 1965, No. 13397/65. Heading G2J. An optical system is stabilized by means comprising at least one set of complementary positive and negative lenses, one lens 29, 32 of each set being fixed with respect to the housing containing the optical system while the other lens 31, 33 is fixed with respect to a gyroscope 38 having its rotor axis parallel to a predetermined line of sight, the sets of lenses thus compensating for small angular deviations of the housing from said line of sight. In the embodiment of Fig. 3 planoconcave lenses 29, 32 are fixed in a camera housing 34 on the optical axis 36. Mating planoconvex lenses 31, 33 are mounted within the housing 34 by means of the gyroscope 38, the gimbals of which are pivoted about axes which intersect at the common centre of curvature of the mating surfaces of the two pairs of lenses. A prism 49 deflects the light entering the camera to a film gate 46. The refractive index of the lens pairs is such that the total deflection produced by the prisms formed, on deviation of the camera through an angle Ï, is also equal to Ï. In order to make the stabilizing means achromatic the lens pair nearest the gyroscope produces a prism having dispersion properties equal and opposite to the total dispersion properties of all preceding lens pairs. A precessor 52 is arranged to move the gyroscope through vertical or horizontal angles to permit intentional panning of the camera beyond the narrow range of angular motion for which compensation is provided. When this compensating device is incorporated into a telescope the total deflection produced by the lens pairs, upon deviation of the telescope housing through an angle Ï, is arranged to be ó (1 Œ1/M,) where M is the magnification power of the instrument. This further correction is necessary to overcome rotation of the line of sight.