www.pilotballoon.com "the pilot balloon web resource" 

Up K & E Photo

The K & E Marine Pibal Theodolite

image of marine theodolite on board the USS Bunker Hill 1943-1944
Photo from U.S.S. Bunker Hill Nov 43'-44'

The marine theodolite is designed with a gimbal and a counterweight.  It is not leveled and aligned like a land based instrument.  Elevation angles are measured with a marine theodolite in the same way that a star site is taken with a marine sextant.  A movable index mirror is used to converge the balloon with the horizon.  The true horizon or artificial horizon (bubble horizon) may be used.  Azimuth is measured the same way as a land based theodolite.  More detail and jpegs of the K & E Marine Theodolite are also available on this site. 

marine.jpg (85515 bytes)

This image scanned from Manual of Winds-Aloft Observations Circular 0, September 1959.  This publication has some pages explaining the operation of this instrument.