The Measurement Valley Laser-Telegraph

Uptdate on August 1st 2016: We have taken the laser down and sent it in for repairs. This will approximately take 3-4 weeks and we hope to get it running again by the beginning of September.


Update on May 2nd 2016: Today's measurements have unfortunately shown that the laser is not working properly at the moment. We are working on the problem and hope to be able to repair it soon. Until then the laser beam cannot be seen very well. In order to decipher the messages you have to look for the dot on the roof of the Sternwarte or the Johanniskirche.


In 1833 Carl Friedrich Gauss and Wilhelm Weber succeeded in sending messages via an electromagnetic data line. 174 years later – since 19th  November 2007 – the Measurement Valley Laser-Telegraph sends encoded messages from the observatory to the St. John’s church.

You are welcome to try to solve the puzzle. All you need is curiosity, open eyes, the code and a good view.
To take notes of the message it suffices to see a small part of the laser beam.

Every night in the sky above Goettingen

Every night, the laser starts on the first full hour after sunset and lasts for two hours. E.g. at the Winter solstice the sun sets at 4:13 pm, the laser starts at 6 pm.



Month Start CET Start DST
January 6 p.m  
February 7 p.m  
March 8 p.m   9 p.m
April   10 p.m
May   11 p.m
June   11 p.m
July   11 p.m
August   10 p.m
September   10 p.m
October   8 p.m   7 p.m
November   6 p.m  
December   6 p.m  

How it works

The transmission of the message begins with a starting sequence, which consists of long and short pulses.
After the starting sequence the real signal transmission begins. The messages are converted with a code developed by Gauss and Weber. Every letter is converted into a combination of long and short laser pulses.
The chart below helps to decode the message.
+ stands for short pulses
- stands for long pulses

Letters and words are separated by pauses of different lengths. A stop signal ends the message. It consists like the start signal of a series of alternating long and short pulses. The message will be repeated over the two hours in which the laser telegraph is working.



Measurement Valley e.V.

Ms Claudia Trepte

Nikolaistraße 29
D-37073 Goettingen