GB190500319A - Improvements in or relating to Range-finding and Sighting Telescopes - Google Patents

Abstract

319. Allen, F. W. Jan. 6. Range-finders ; telescopes.--To enable a rangekeeping telescope, particularly of the kind described in Specification No. 17,209, A.D. 1902, to be used also as a sighting-telescope for heavy ordnance, the magnifying power is changed quickly by a removable system of lenses. Fig. 3 shows a removable afocal system of lenses 16, 17, 18, similar to an operaglass system, arranged between an eyepiece of the Ramsden type 5, 6, and an erecting eyepiece 9, 10. The convex lenses 5, 6 are mounted in a tube 8, and the focus of the system coincides with that of the object.glass 7. The convex lenses 9, 10 are mounted in a tube 14 and have a common focus, at which is arranged a piece of plane glass 11 with a vertical wire or line and an horizontal arrow head to facilitate sighting. The lenses 16, 17, 18 are shown mounted in a thin metal tube 19, which may be moved out of action into a light-proof casing 21, Fig. 2, by a handle 23 pivoted at 24. When the lenses are brought into operation, their correct position is determined by a stop 22 secured to the telescope casing by screws.