GB572506A - Improvements in or connected with binocular observation instruments - Google Patents

Abstract

572,506. Binocular telescopes. BARR & STROUD, Ltd., and FRENCH, J. W. Oct. 26, 1939, No. 28748. [Class 97 (i)] The object fields of the limbs of binocular telescope instruments are arranged to differ wholly, or to a substantial extent, to increase the total field of view ; the images seen by the observer may be contiguous, overlapping, superimposed, or separated, and may be of the same or different magnifications. The instrument may comprise two objectives, or one only, and two instruments having, respectively, horizontally and vertically separated object fields may be mounted in fixed relative positions. Fig. 4 shows diagrammatically, objectives 1, respectively arranged for observation of fields depicted by circles AB and CD, inverted images BA, DC being produced. Means for producing therefrom erect and differently oriented images in the focal planes of eye-pieces 5 are provided, the magnified images A<1>B<1>, C<1>D<1> being visible to the eyes 3 as contiguous images. Field diaphragms of various shapes may be used and different forms are described. Various modifications of the arrangement of Fig. 4 are described, the eye-pieces having divergent or parallel axes, the object fields being in different relative positions, and the instrument being of the prismatic or Galilean type. Fig. 45 shows an instrument having a single objective producing images AB, CD in conjunction with prisms having reflecting surfaces 10, 11, 12 and 13, 14, 15 ; a roof type reflecting surface may be provided on each prism. Modified Porro prism combinations for erecting and orienting the objective images are described. Adjustment of interocular separation of the eye-pieces may be provided for by making one limb movable on parallel guides relatively to the other, by providing a hinge pin 44 &c., as in Fig. 56, or by providing a vertical hinge 51, Fig. 65, about which the limbs may swing. Scales may be associated with the adjusting means, for example, a scale 56, Fig. 65, in conjunction with a steadying extension 54 sliding within an extension 55. Alternatively, a step prism 57, Fig. 72, rotatable with its associated eye-piece 58 about an 'axis x25, may be provided for interocular adjustment without change in the appearance of the fields.