In my last post regarding this watch, I told you that I was lucky enough to receive an original leather case with star disk as a gift from a very kind German gentleman that frequents the forum I moderate.
One of the other things it was missing is the original dial with the "Sternzeit reguliert" print. I was expecting a long and difficult search to find one. However another German gentleman collector that prefers to remain anonymous offered to help me. And the day before yesterday the package from Germany arrived. Not only was I very lucky to buy a Sternzeit without knowing it, I've been greatly helped twice already now to make the package complete.

Today I went to my watchmaker, with the Heuer and the Sternzeit dial. I also took Konrad Knirim's excellent book "Military Timepieces" to show the watchmakers (there's five working together in this shop) the history of this particular model.
An interesting discussion followed. One of the things I wanted to have them do, is regulate the watch to sidereal time ("Sternzeit"). A star day is only 23hr 56m 3.5sec. At home I had already done the calculations. The movement in this Heuer is the Valjoux 230 fly back chronograph that normally runs at 18000 bpm. If you want it to go around the dial twice in 23hr 56m 3.5sec, it should run at 18050bpm. So I asked the gentleman helping me if he could regulate it to run at that frequency. This was obviously a somewhat out of the ordinary question, and even with the help of Konrad's book, he could not be convinced that it made any sense to do that. In his opinion, if you make it run faster, you should also modify the dial, to indicate 23:56:3.5 instead of 24 (or 12) on top. I'm afraid that Germany lost a little respect as a top industrial nation in this particular watchmakers shop .
The Heuer went on the timing device anyhow, and it proved to run exactly at 18000bpm as expected. Somewhere during it's service life (or maybe even after that) the dial was changed to a regular one, and the timing adjusted to run like a normal watch. Rather quickly the adjustment was made to 18050bpm, so its running on sidereal time again now. Just like in the service, to avoid mistakes, I then had the dial changed. One of the other watchmakers (a big Speedmaster fan, and very knowledgeable on that subject) enjoyed the Heuer greatly, and changed the dial there and then. The movement looked perfect, and ran perfect, so a service would have been a waist of time and money.
Here's the result.