The Heuer Bundeswehr Flyback chronograph was made for the German army between the 1960s and 1970s and is one of the most desired chronographs by collectors. There were several variants of the "Bund" and the rarest specimen we see here is the "Sternzeit Reguliert".

The above term translates into sidereal time and is a way of indicating the time based on the rotation of the Earth in relation to distant stars. Consequently, a sidereal day lasts 23 hours and 56 minutes, while the solar day is 24 hours.

This variant was used exclusively by the artillery forces, which used sidereal time together with the positions of the optical theodolite to determine the horizontal and vertical planes in order to accurately launch rockets. It was important to know where you were in order to assess the exact distance from which to throw bullets.

It is estimated that only a few such examples exist today (50-150 by estimates), making it one of the rarest military watches.