Description:
The first chronograph of Heuer-Leonidas for the Bundeswehr was Leonidas (cal. Valjoux 22) in relatively rare items and accordingly interesting for the collector. Next came Heuer and Sinn (cal. Heuer 1550 equal to Vx 23) in the same steel case like the Leonidas but with a somewhat different movement. The models of Heuer and Sinn are identical. The reason is that Sinn was the German supplier for Heuer of Switzerland.  
 
The chronograph of Heuer was supplied in a very interesting variation together with a theodolit for astro navigation, but regulated in sidereal time (cal. 1551 SGSZ).  Vers.-Nr.: 6645-12-148-2298.
 
Movement:   Valjoux MN 230, flyback function,  36 h  17 jewels, max. + 10 s/day, max. pressure: 3 bar, working temperature: -18 C to 6o C,  Incabloc-shock resist,  antimagnetic, H3- luminescent, year of introduction: 1968, weight: 50 g, producer: Heuer-Leonidas S.A. Biel, Switzerland.  
 
Application:
All hand-worn models had the flyback function similar to those of the Third Reich Air Force and to those of the French Air Force, which allowed the chronograph to be pushed back to zero while running, with the capability of immediate restart.  
This chronograph is regulated to sideral time and is part of an equipment for astronavigation ‘Vermessung Theodolith 6675-12-140-9136’ and to ‘astronomische Richtungsbestimmung,Vers.Nr. 6675-12-308-8782 ’ in a nice leather case.
 
The chronograph was used to get the time while observing the azimut in astronomic measurements. A sun year has 365 days, a.sun day has 24 hours, because of the earth moving around the sun in one year a  sideral year has 366 days starting in spring and a sideral day has 23 hours, 56 min.and 3,5 seconds. So for fast astronavigation a watch or clock regulated in sideral time saves the calculating effort.
 
This watch has a separate reg.-no. and referance and is marked on the dial. The amount of pieces produced may be 50, so they are very rare.

Description:
The first chronograph of Heuer-Leonidas for the Bundeswehr was Leonidas (cal. Valjoux 22) in relatively rare items and accordingly interesting for the collector. Next came Heuer and Sinn (cal. Heuer 1550 equal to Vx 23) in the same steel case like the Leonidas but with a somewhat different movement. The models of Heuer and Sinn are identical. The reason is that Sinn was the German supplier for Heuer of Switzerland.  
 
The chronograph of Heuer was supplied in a very interesting variation together with a theodolit for astro navigation, but regulated in sidereal time (cal. 1551 SGSZ).  Vers.-Nr.: 6645-12-148-2298.
 
Movement:   Valjoux MN 230, flyback function,  36 h  17 jewels, max. + 10 s/day, max. pressure: 3 bar, working temperature: -18 C to 6o C,  Incabloc-shock resist,  antimagnetic, H3- luminescent, year of introduction: 1968, weight: 50 g, producer: Heuer-Leonidas S.A. Biel, Switzerland.  
 
Application:
All hand-worn models had the flyback function similar to those of the Third Reich Air Force and to those of the French Air Force, which allowed the chronograph to be pushed back to zero while running, with the capability of immediate restart.  
This chronograph is regulated to sideral time and is part of an equipment for astronavigation ‘Vermessung Theodolith 6675-12-140-9136’ and to ‘astronomische Richtungsbestimmung,Vers.Nr. 6675-12-308-8782 ’ in a nice leather case.
 
The chronograph was used to get the time while observing the azimut in astronomic measurements. A sun year has 365 days, a.sun day has 24 hours, because of the earth moving around the sun in one year a  sideral year has 366 days starting in spring and a sideral day has 23 hours, 56 min.and 3,5 seconds. So for fast astronavigation a watch or clock regulated in sideral time saves the calculating effort.
 
This watch has a separate reg.-no. and referance and is marked on the dial. The amount of pieces produced may be 50, so they are very rare.