Observation watch
A deck watch , even B-AM or Deckuhr called, is a portable clock in pocket format , which for navigational was intended purposes. Observation watches had to have an official certificate.
Similar clocks were also used in astrometry and astrogeodesy until around 1970 , where they mediated between the measuring instrument and the time signal and were called work clocks .
criteria
The construction of this type of clock, which was used as a portable precision clock primarily for navigation purposes, had to meet the following criteria :
- High quality movement
- High quality escapement
- Compensation of the gear regulator
- Large dial , clear display
history
The era of the powerful marine chronometer began around 1780 . Because of the positional sensitivity of the escapement system, these clocks were gimbaled and housed stationary.
Need for development
Some reasons that accelerated the development of a portable precision watch:
- Before starting the voyage, the sea chronometer first had to be synchronized with the time in the port, whose longitude was known. For this purpose , this time had to be brought to the ship from the nearest observatory , where precise time measurements were carried out on an astronomical basis. The precision pendulum clock set up in the observatory was of course stationary. For the "time transport" between the observatory and the ship, accurate, portable clocks of small format were needed. The chronometer could neither be set nor regulated. Therefore, only the difference between the sea chronometer and the time taken on board was entered in a book.
- The process of determining length on board was not easy. An accurate portable watch of small format was necessary, especially for the seafarers who were not only dependent on the built-in ship's chronometer, but with the help of the "deck watch" or "observation watch" at various points on the "deck" calculations and measurements, i.e. the " Observations ” to determine the position of the ship.
- The numerous research expeditions that took place at this time also required accurate, portable clocks for precise geographical location and time determination. These watches were called pocket chronometers or precision pocket watches . Alexander von Humboldt used a Breguet pocket chronometer on his American research trip (1799–1804) .
The development of this type of clock is therefore closely related to the actual marine chronometers and the observation clocks were made by the same watchmakers or companies.
See also: astronomical navigation , length problem (historical) , length clock
Classification of clocks
In the first half of the 20th century, the greatest number of B-clocks were manufactured for military purposes.
From this period, observation clocks can be divided into three subgroups:
- Chronometer watches (pocket chronometers)
- Deck clocks
- Precision watches
The table shows the classification of watches in three European countries.
| Observation watch | German Empire | England | France |
|---|---|---|---|
| 1. Chronometer watch | B – o'clock, 1st class |
Chronometer Watch H.S. 2 |
Chronomètre de Bord Montre de Torpilleur |
| 2. Deck clock | B – o'clock 2nd class |
Deck Watch H.S. 3 |
Compteur |
| 3. Precision watch | B – Uhr III class |
Deck Watch H.S. 4 |
Compteur |
Observation watches were widespread until the end of the Second World War and were also used in the navy afterwards.
Aviator observation watches in World War II
On the basis of the Reich Aviation Ministry in the Fl. 23,883 formulated requirements for observation watches for the German Air Force, various manufacturers were obliged by resolution in 1940 to start production according to strict specifications.
During the war years, the following manufacturers produced pilot watch watches:
- IWC, Schaffhausen
- Stowa, angel brand
- Wempe, glassworks
- Lange & Söhne, Glashütte
- Laco , Pforzheim
It is falsely claimed that the historical aviator watch watches were worn by pilots. Instead, it was the navigators on board who, in combination with an octant (protractor), were able to determine the exact position of the aircraft. The pilots themselves wore i. d. R. chronographs, e.g. B. from Hanhart or Tutima, as a reserve in case a clock should fail.
Observation watches or observation wristwatches had some typical features: The exact specifications of the B-clocks according to the construction instruction Fl. 23883 of the Reich Aviation Ministry (RLM) saw z. E.g. a large diameter of 55 mm and a large onion-shaped crown so that the navigators could operate the watches with gloves. There are two types of pilot's observation watches: Type A had a triangle with two points instead of the Arabic “12”. This is also the case with type B , except that instead of the Arabic numbers 1 to 11, the seconds are printed in steps of 5. The classic hour division from 1 to 12 is located in an additional inner ring.
The number of the building instructions (Fl 23883) is engraved on the edge of the case and on the base of the historical observation watches. Also manufacturer, type, device no. and the work description were on the steel floor.
The decline of the B-Uhr only came in the second half of the 20th century with the invention of the quartz clock , the accuracy of which immediately improved by three powers of ten . The B-Uhr as a navigation instrument lost its raison d'etre. Nowadays ships use GPS ( Global Positioning System ) for navigation , but means for determining position using astronomical methods (i.e. tables and devices) are still required.
To this day, various manufacturers produce observation watches for collectors and enthusiasts. As a result, the term “observation watch” has expanded from the pocket watch to the wristwatch .
construction
plant
Observation watches from the 20th century show the whole range of technical developments in watchmaking. The movements were very precisely manufactured and usually mounted on 16-22 jewels . The predominant escapement is the anchor escapement . With English watches the pointed lever escapement , with all others the Swiss lever escapement . Watches with a chronometer escapement or tourbillon were only used for experimentation. The regulator is always of excellent quality and temperature compensated.
Dial
Clear readability of the indications and numbers has always been part of the specifications. Until the Second World War, Roman numerals were preferred , later Arabic numbers . A power reserve display was also required for observation watches that were to be used instead of marine chronometers .
casing
Cases for observation watches are generally simple, solid and functional. They are modified for the function of the clock, e.g. B. extended pushers for setting the hands, omitting the glass, etc. Most clocks from the 20th century have nickel alloy or stainless steel cases. Silver cases were rarely used.
box
Only American observation watches were equipped with a three-part wooden box, like a marine chronometer. Other procurement agencies content themselves with simple wooden boxes, upholstered, or with brass boxes.
Observation watch suppliers
The procurement policy of the individual states was quite different. In all of them, however, unnecessary technical equipment was saved. Procurement authorities bought precision and accuracy, not beauty.
Germany
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Despite great efforts, Germany remained dependent on watches from Switzerland.
United States of America
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Soviet Union
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France
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England
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literature
- Gisbert L. Brunner , H. Sinn: Observation wristwatches - a comparison. In: Old clocks. Volume 3, 1983, pp. 243-246.
Web links
- Literature from and about observation clock in the catalog of the German National Library
- watch-wiki: observation watch / B-watches
- National Maritime Museum, Greenwich: Deck watch (english)
Individual evidence
- ↑ PocketWatch PocketWatch - Lexicon D. Archived from the original on December 17, 2007 ; Retrieved August 13, 2012 .
- ↑ Lukas Stolberg: Lexicon of the pocket watch. 4th, completely revised edition. Carinthia, Klagenfurt 1995, ISBN 3-85378-423-2 , p. 36.
- ↑ Gerhard König: The clock. History, technology, style. Koehler & Amelang, Berlin et al. 1991, ISBN 3-7338-0065-6 , p. 279.
- ↑ Johann Gottlieb Geißler (ed.): The watchmaker or teaching term of the art of watchmaking. Eighth part. Crusius, Leipzig 1797, p. 150f.
- ^ Hans von Bertele : Marine and pocket chronometer. History, development, impact. Callwey, Munich 1981, ISBN 3-7667-0512-1 , p. 110f.
- ↑ Bobby Schenk : Astronavigation. Without formulas - practical. 9th edition. Delius Klasing, Bielefeld 1994, ISBN 3-7688-0259-0 .
- ↑ PocketWatch: observation watch
- ↑ Horst Hassler: Time and Time Determination at Sea, Lecture (PDF; 1.6 MB)
- ↑ Steffen Röhner: Military pocket watches. The manual for collectors. Callwey, Munich 1992, ISBN 3-7667-1048-6 .
- ↑ Konrad Knirim: Navigation clocks for the German Air Force (PDF) 2004. Retrieved on January 24, 2019.
- ↑ Chrononautix.com: The observation watches from Laco and other manufacturers. (No longer available online.) August 16, 2016, archived from the original on August 16, 2016 ; accessed on August 16, 2016 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Poljot: observation watch ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ uhren-schmuck.de: The reinterpretation of the scientific observation clock
- ↑ Lange Uhren GmbH: The Zeppelin observation watch ( Memento of the original from January 4, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Tony Mercer: Chronometer Makers of the World. With extensive List of Makers and Craftsmen. Revised edition. Robert Hale, London 2004, ISBN 0-7198-0340-3 .
- ↑ watch-wiki: A. Lange & Söhne observation watch caliber 48
