B-Uhr project: The history of Observation watches | Part 1.

Text by Gisbert Brunner, curator and Watch Angels community advisor for the Watch Angels B-Uhr project

Watch Angels
Watch Angels
Published in
5 min readNov 30, 2021


Military observation wristwatches

Observation watches are precision instruments that were mainly used by the military, research institutions, and air and seafaring to monitor and compare time.

They could be designed as pocket or wrist watches.

Like the seafaring, whom required clocks that were as accurate as possible to determine the geographical longitude on board, pilots were also dependent on equally precise, robust, and easy-to-read clocks to determine location and flight duration.

Exact time above all

The history of observation watches is part of the history of navigation and flight, and it starts at the end of the Middle Ages.

The conquest of the earth enjoyed immense importance among the seafaring nations. But for this, the exact location determination was indispensable. While the determination of the geographical latitude with the help of sextants and other astronomical devices for observing the position of the stars hardly caused any difficulties, the determination of the geographical longitude was one of the greatest challenges of civilized mankind.

1700 Dutch Vessel
HMS HMS Royal George 1756

Anyone who mastered positioning in the vastness of the oceans was definitely one step ahead. Therefore, Philip III of Spain in 1598, the States General of the Netherlands in 1610, the English Parliament in 1714 and the French Regent in 1716, awarded big sums of money to whom would come with the solution to determine longitude.

Incidentally, seafarers and astronomers had known the immense importance of precise wheel clocks since the 16th century. They were used to record the local time of the last port of known geographic longitude as precisely as possible over long distances. In 1721, Sir Isaac Newton stated, because there was a lack of it: “A good watch may serve to keep one’s bearings for a few days at sea and to tell the time for observing the sky, and it will serve this purpose until a better kind of watch is found. As soon as one has lost the length at sea, however, it cannot be found again by any watch. “

After all, a minute deviation in our geographical latitudes leads to a length error of 15 kilometers. At the equator the error becomes even of 27 kilometers. And that is quite a lot in the vastness of the oceans. You can imagine what financial damage in terms of time and money a non-precise watch would do!

It is for this reason that Captains on Her Majesty’s ships as well as merchants and owners of merchant ships sent an urgent petition to the English Parliament in early 1714 to solve the problem of length. In the so-called “Longitude Act”, enacted by Queen Anne on July 8, 1714, the government awarded the considerable prize money of 20,000, 15,000 or 10,000 pounds sterling (about 4, 3 or 2 million pounds of today!) for the determination of the geographical longitude with a deviation of ½, 2/3, 1/3 or a maximum of one degree of arc. In terms of watches, the £ 20,000 gain meant a maximum daily rate deviation of +/- 3 seconds.

John Harrison

This is where John Harrison comes in. From 1730 the self-taught horologist developed various chronometers. His most important, the H4, completed in 1759, fulfilled the high requirements.

John Harrison’s H4

Nevertheless, the specially appointed Longitude Commission held him out until 1765. Only then, close to desperation, could he finally accept half of the premium.

The board of Longitude

In 1773 an act of grace by the government gave him an additional £ 8,750. After all, this timepiece went wrong by just five seconds in total during an 81-day voyage in 1762. However, envious competitors didn’t really want to acknowledge that.

Be that as it may: Harrison’s ingenuity and persistence made ship navigation possible with unimagined accuracy. The well-known ship chronometers were derived from the pioneering achievement of the Englishman, which, because of their immense importance for determining the location in the event of an accident, were always salvaged first. Every winding operation had to be recorded in detail in the chronometer logbook. And if the person in charge forgot to wind the instrument, draconian punishments such as keel-killing threatened.

Next episode: “Marine chronometers and pilot observation clocks”.

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Gisbert L. Brunner, born in 1947, has been working on watches, pendulum clocks and other precision timepieces since 1964. During the quartz clock crisis of the 1970s, his love for the apparently dying-out mechanical timepieces grew. His passion as a hobby collector eventually led to the first newspaper articles in the early 1980s and later to the by now more than 20 books on the topic.
Amongst others, Brunner works for magazines such as Chronos, Chronos Japan, Ganz Europa, Handelszeitung, Prestige, Terra Mater, GQ and ZEIT Magazin. He also shares his expertise on Focus Online. Together with a partner, he founded the Internet platform
www.uhrenkosmos.com in 2018. After the successful Watch Book I (2015) and Watch Book II (2016), the teNeues publishing house published the Watch Book Rolex, written by Gisbert L. Brunner, in June 2017. The book has appeared in German, English and French and has already been reprinted several times due to high international demand.