www.pilotballoon.com "the pilot balloon web resource"
This Italian Pilot Balloon theodolite is of unknown vintage. It is very similar to the Askania theodolite on this site. It is likely that the Siap is derivative of the German Askania design. The Siap has two separate telescopes systems, unlike its American or British contemporaries. A number of German designed pilot balloon theodolties are set up this way including the Askania theodolite, the Askania recording theodolite and the currently produced Breithaupt pilot balloon theodolites. The theodolite has two vertical circles (200 degree arcs) and two vernier sets allowing it to be read from the front by the observer or from the back by a second person. Lighting is only provided on the rear set of scales
This instrument was acquired in 2006 from a seller in Canada.
This theodolite has accessories in the lid of the case including the electrical connection, the lighting units which are removable and three colored eyepiece filters. The theodolite case is threaded allowing the case to be mounted to a pier and the theodolite leveled and operated while still attached to the bottom of the case.