Battenberg Course Indicator Mk III, Mounted for Display A-35 Vengeance The float is suspended so

The float is suspended so that the needles are free to align themselves horizontally with the earth's magnetic field

It is full of illustrations and diagrams

This periscope was mounted by inserting the unit into a bracket and hooked onto a lip (the 'hook' is visible in the photos)

and the night-fighter N versions equipped with AN/APS-6 radar system

and B-29 Superfortress

Battenberg Course Indicator Mk III, Mounted for Display A-35 Vengeance The float is suspended soHere is an original naval Battenberg Course Indicator Mk III. The Battenberg course indicator is a mechanical calculating device invented by Prince Louis of Battenberg in 1892 for taking station on other vessels whose range, bearing, course and speed are known. By extension, it has a range of other functions related to relative velocity calculations. A number of versions of the device were produced and it proved particularly useful for station