New moon

Watch news and tools for
collectors and the curious.

Accuracy

How many seconds a day your watch gains or loses, heard through your phone’s microphone.

Ferdinand Berthoud Chronomètre FB 4BTC FB 4BTC.1
Ferdinand Berthoud · FB 4BTC.1

Chronomètre FB 4BTC

Change

Somewhere quiet, lay the watch caseback up on something soft. Rest the bottom edge of your phone on the caseback and keep both still.