GB749690A - Improvements in or relating to telescope systems - Google Patents

Abstract

749,690. Telescope systems. COOK, G. H., and KAPELLA, Ltd. April 28, 1954 [May 1, 1953], No. 12140/53. Class 97 (1). A telescope system, particularly intended for an alignment telescope comprises an objective formed in two parts, the front part being afocal and having telescopic power greater than unity so that an incident collimated beam will emerge from the front part as a collimated beam of smaller diameter to fall on an adjustable optical deviating device arranged between the two parts of the objective so as to displace the image formed by the whole objective on a graticule and which is observed in an eyepiece. As shown, the afocal front part of the objective comprises a convergent doublet A fixed relative to a negative component A<SP>1</SP>, the light deviating means comprising a plane parallel plate C being located between the component A<SP>1</SP> and a fixed doublet B, and the objective. being completed by a doublet B<SP>1</SP> mounted in a tube axially movable for focusing by a rack B<SP>5</SP> engaged by a rotatable pinion (not shown), the tube being restrained from rotation by a pin and slot B<SP>4</SP>, B<SP>3</SP>. Numerical data are given for one such objective in which the component A<SP>1</SP> is a doublet and for one in which the component B<SP>1</SP> is omitted, the component B being axially movable for focusing. The objective forms an image in the plane of a graticule D which can be observed in an eyepiece D<SP>1</SP>, D<SP>2</SP>. The light deviating plate C is supported in an annular mount C<SP>2</SP> having spherical surfaces engaging within a cell C<SP>1</SP> and being supported by a fixed ball C<SP>4</SP> and balls C<SP>5</SP>, C<SP>6</SP> at right angles thereto and carried by links E, E<SP>1</SP> respectively. The links have projections respectivey engaging rotary cams E<SP>4</SP>, E<SP>5</SP> moved by knobs E<SP>2</SP>, E<SP>3</SP>, rotation of both of which causes rotation of the block C about the ball C<SP>4</SP> and rotation of one of which causes rotation of the block about an axis joining the other two balls. The block C may be replaced by two similar blocks rotatable independently or linked for simultaneous similar rotation. The front of the telescope may carry a target which can be observed in a distant mirror to test the alignment thereof with the telescope axis. Also the graticule D may be illuminated by light from a lamp N, Fig. 16, which may be plugged into the telescope, the light passing via a condenser N<SP>5</SP> to a semi-transparent reflector N<SP>3</SP> or a beam splitting prism which directs on to the graticule' and allows the light-which is reflected back by a distant mirror to pass to the eyepiece. The afocal part of the objective may comprise a single compound component or a suitably arranged separated triplet system.