It's that time again: In the night from Saturday to Sunday, the clock is set forward. While this is often done automatically with cell phones or radio-controlled alarm clocks, there is a lot of work behind the changeover of Cologne Cathedral's clock.
Interviewer: The clock in Cologne Cathedral still runs mechanically and not electronically. You personally will turn the clock on the night of the time change from Saturday to Sunday. How does it go then?
Jorg Sperner (assistant to the Cologne Cathedral master builder): There are two of us. The master watchmaker, who restored the clock in 2018, is also present. He is an expert and restorer of clocks. I will stand by him. Of course, he doesn't miss the chance to do it himself again in this case.
Interviewer: When changing to winter time in autumn, the process is easier. There the clock is simply stopped, or?
Sperner: Yes. The pendulum is stopped in the fall at the time changeover. Now in the spring we have to "steal" the hour. That means we have to lend a hand and get the cathedral clock to strike not two o'clock but three o'clock.
Interviewer: And how do you do that??
Sperner: There is a mechanism on the back where you can set the hour strike. This is turned to the front. Theoretically, it's a very simple matter, especially for watch restorers and watch experts. For me, this is still an exciting matter.
Interviewer: You then climb the 100 steps up to the second floor. There is the mechanical clockwork from 1880. And then the tension rises?
Sperner: One does not do it so often. That's why the tension is already there. Of course, you also need a certain amount of concentration to know what you are doing. You don't want the whole of Cologne to get a wrong stroke of the clock.
Interviewer: Can anything go wrong??
Sperner: It can be adjusted. It can slip further. That means that the time is not correct. At the moment it is almost to the second. If you turn it, it's already possible that the clock will be set incorrectly.
Interviewer: And then, of course, you have to check on the spot whether it really worked now. That is, you stay then also first at the top of the clock?
Sperner: Correct. A check is made. Every quarter of an hour there is a chime. The clock is connected to the bells and the interaction with the sound we can then control. We will certainly wait until three o'clock, until the strike is made on the hour.
Interviewer: Now the time change has been around for quite a few years now. Did something happen there at some point, so that the changeover didn't work out?
Sperner: Fundamental has not happened. But it has happened before that the time change did not work exactly to the second. But this will be corrected during the night. You then have to work at it until the time is really right.
Interviewer: Have you ever received feedback from the people in Cologne if something wasn't quite right after all??
Sperner: We will certainly be made aware if the cathedral does not strike the right time. Then there are calls, either before or after the hour, with the tenor: "That's not possible."
Interviewer: Now the time change will soon be history. Will you miss something?
Sperner: Not at the moment. I then look forward to a night that I can sleep through. When the time comes, I will surely miss something. But I can also visit the cathedral clock like this.
The interview was conducted by Carsten Dopp.