Junghans Meister J880.1 Manual Del Usuario página 10

Setting the date and day of week Technical information
Do not
make any changes to the date between 08:00 p.m. and 02:00 a.m.,
as the date is automatically advanced by the movement during this
period and you could damage the date advance mechanism.
Using the chronoscope
Starting time measurement:
Stopping time measurement:
Reset:
Adding measured times: