Martin Brenner's, Pilot Balloon Resources 


WWII Vintage Tamaya Pilot Balloon Theodolite

The theodolite below was produced in 1943.  It is the same model as used by Imperial Japanese Airforce during WWII this instrument also shows a navy anchor on its box name plate.   As with the Tamaya Model BT-901 the main objective is not aligned with the horizontal center making this unit less than desirable for doubling as a surveying instrument.  This theodolite includes lighting for the reticule (main eyepiece, only) and the azimuth and elevation scales.  Unlike American designs and later Tamaya models, it uses two completely separate telescopes for wide angle and high power viewing. 

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This view shows the circular compass as well as one of the hand wheels.  You can also see one of the bubble levels. In this view you can see the lighting unit for the main (high power) objective, as well as the DC power connector for the lighting system. 
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In this rear view the scales (vernier) are visible along with both hand wheels.  This instrument is a two person instrument.  An observer and a recorder.  The scales cannot be read by the observer on this model.  In the next model the scales were relocated to the front side where they could be read by the observer. In this view you can see a bit of the redicule rheostat knob (under the prism for the main telescope).  An interesting feature here is that the electrical system uses a brush arrangement to conduct electricity to the reticule lamp when the telescope is moved.  In all other designs I have seen a wire is just run along the telescope and bends as the instrument is moved.

The bubble levels on this theodolite have protective metal cylinders covering the glass.  These covers can be rotated to expose the levels and closed to protect the levels from damage. 

Prior to my acquisition this theodolite was in in the collection of a retired military officer in Australia who claimed it was liberated during the second world war.  
Drive Type Friction/Worm Compass Yes (detachable)
Display Type Vernier to .1 degree
(viewed back side)
Levels 2, plate,  bubble tube
Main Telescope   Mounting 3 leveling screws
Finder Telescope
dual eyepiece
Illumination 2, 3, volt scales
Gun Site Yes 1, main telescope Weight  

Thanks to Rich Lane for pointing out the correct date of manufacture of this theodolite 18, 8 corresponding to 1943 and also pointing out the existence of the navy symbol on the label of this instrument.