Abstract: An adaptor for mounting one instrument, such as an electronic distance measuring device, atop another instrument, such as a telescope or theodolite, for movement together about a horizontal axis with a base member attached to the upper device and presenting two downwardly facing cam surfaces and support members engaging the cam surfaces for vertical movement against springs to counteract the forces produced by the upper instrument as it pivots.

Abstract: An apparatus including a frusto-conically shaped tube for transmitting light with internal reflection surfaces which diverge in the direction from input to output. Incident light from an LED or other substantially phase coherent source is mixed by internal reflection of rays incident at greater than a predetermined angle to minimize the non-uniform phase front and concentrate the beam to permit greater transmitted power. The apparatus finds particular utility in distance measuring instruments in which the output of the tube is directed to an object and the phase of the reflected light compared with the phase of the transmitted light to determine the distance.