One of the instruments I obtained early on. It was listed as a 'sextant' which it obviously wasn't. Didn't take me long to figure it was a theodolite but then the mystery started. No brand (only 'YAL') and a design I had not seen before. It came with a power box and a mechanical clock marked 0 to 60. After some research I figured that YAL is actually a military abbreviation and relates to a production year by Meopta in one of their factories after the merger with Optikotechna and Srb & Stys. The instrument is almost an exact copy of similar theodolites produced by Askania Werke in Germany. As Askania had factories in what was, after WWII, the iron curtain it is most probable that the designs were 'reused' by Meopta. With this information I figured out this was actually a 'balloon' theodolite.

A balloon theodolite is for following a weather balloon and charting its course. For this the position of the balloon (horizontal and vertical angle) is measured at regular intervals (hence the clock that was included). Normally two observers are required, one to follow the balloon and one to register the readings. This theodolite has two telescopes with different magnifications that allow the balloon to be followed during different parts of its trajectory. Both telescopes can be viewed at the same time but I assume that only one would be focussed at at a time.

There is a word of WARNING concerning this instrument as I found out at a later moment that the clock is actually radioactive. This is the result of radium 226 paint on the hands and dial. Radium has a tremendously long half life of 1600 years so after 50 years most of the original radiation is still there. In the 1940s to 1960s radium was used extensively in dials of instruments and watches but later found to be harmfull in certain cases. In this clock the dials were no longer emitting light but a geiger counter shows the radioactivity. The main issue with the radium paint is not so much the radiation in free air but the fact that, once ingested or inhaled, it can become carcinogenic quite rapidly. In the Netherlands it is illegal to own radioactive substances and I had to surrender the clock to the authorities (who presumably disposed of it in a safe way). Ever since I have a Geiger counter that I use on new acquisitions to detect any radio activity. So if you own something with Radium 226 and its legal to keep, handle it with gloves to avoid contamination and stay at least 1 m away from it at all times and only for very a very short while at a closer distance.