Martin Brenner's, Pilot Balloon Resources 


CFJ-IIB or Weather Measure Model 8304 Theodolite (pibal theodolite)

This theodolite model was imported (from China) by Weather Measure Corp in 1986.  (The instrument photographed is the production sample).   It appears that not too many were imported.  The final unit sold out of inventory was reported to be machine number 27.  (An electronic version was also produced however I do not think that it was imported to the US.)  The model number 8304 appears to be created by Weather Measure and does not appear in the Chinese import document.  It is odd that a number so close to the popular Warren-Knight instrument was chosen.  This instrument is clearly not a derivative of the Warren-Knight instrument.  I suspect that this instrument was influenced by the Russian AWT Instrument and the Soviet ATK-2 Instrument.   

This theodolite is one of the two most modern designs (for a non digital) theodolite that I have seen.     It uses friction driven glass circles which are read through the eyepiece.  Its optical path is similar to the ATK-2 The verniers read directly to .1 degree and they are set up so they can be read very rapidly.  This theodolite is very compact and light yet features a large 50mm main objective (25 power), 10mm finder scope (3.5 power) and gun site.  It also includes a detachable compass, filters, a lighting system, tools and a case. 

illustration of scale desplay in the theodolite eyepiece

A unique (shared with the AWT instrument) aspect of this theodolite is that the reticule assembly is mechanically connected to the body of the theodolite not to the eyepiece tube.  This allows the cross to maintain its vertical orientation regardless of the elevation of the telescope.  

The theodolite in case weighs only 8.8 pounds, and 16.5 in its case as compared to the Warren-knight 20-8403 which is on the order of 40 pounds in its case.

Photo of theodolite case and accessories Photo of theodolite front view
Photo of theodolite left rear view photo of theodoite right rear view

In the photo above left you can see the empty receptacle for the scale illumination lamp. To the left of that is scale illumination mirror.  The hinged cover  on the top of the theodolite contains the  mirror for viewing the single bubble level that the theodolite contains.

Drive Type Friction/Worm Compass Yes (detachable)
Display Type Vernier to .1 degree
(viewed in eyepiece)
Levels 1, top,  bubble tube
Main Telescope 50 mm 25x Mounting Tribrach
Finder Telescope 10mm 3.5x
single eyepiece
Illumination 2, 6 Volt LED, scales
Gun Site Yes 1, main telescope Weight 4kg