5 Fascinating Facts About The History Of Theodolites

If you are visiting our site, chances are you probably already know that a theodolite is a common type of surveying equipment used to measure vertical and horizontal angles. However, the theodolite is a device used by many professionals other than surveyors, and these devices have a fascinating history. Because we love theodolites, we have compiled a short list of 10 amazing facts about theodolites.

1. Theodolites Have Been Around For Centuries

Surveying equipment has been used since ancient times, but the theodolite has only been in existence since about the 16th century. Prior to this time, surveyors would have to use one device to measure vertical angles and one device to measure horizontal angles.

2. Who Invented The Theodolite?

Actually, there is some debate regarding the answer to this question. Leonard Digges, an English mathematician, typically is credited with the invention of the theodolite around 1550. However, images of a similar device show up in an earlier text, so while he might not have been the first person to think about creating a device that could measure in both planes, he was the first to name it a “theodolite” and create his own working version. He described the instrument in his text, “Pantometria.” If you wish to get up close and personal with a 16th Century theodolite, one similar to Digges’ theodolite is on display at the National Maritime Museum in Greenwich, England.

3. The Great Theodolite Joined France & England

During the 1780s, during a rather brief moment of peace between England and France, British and French astronomers decided that it would be an excellent notion to fix the relative positions of the Royal Observatory in Greenwich and the Paris Observatory. To accomplish this feat, they needed a massive theodolite, capable of being able to mark accurately over a distance of 70 miles. This theodolite, often call the Great Theodolite, was created by Jesse Ramsden, a famous British instrument maker.

4. Ramsden’s Theodolite No Longer Exists

The Great Theodolite, which also is known as Ramsden’s Theodolite, was kept secure for 150 years at the Ordnance Survey in Southampton, England but unfortunately was a casualty of World War II. The Ordnance Survey was bombed by the Germans, destroying the structure, and from all accounts, the theodolite was melted by the heat of the blast. However, Ramsden created several theodolites, and his second one can be viewed at the Science Museum in London, which also includes a huge collection of interesting instruments.

5. Lewis & Clark Used Thomas Jefferson’s Theodolite

As they set off on their epic journey to chart and survey the Louisiana Purchase, Meriwether Lewis and William Clark took along a wide array of mathematical instruments. These included a portable microscope, hydrometers, a pocket compass and a theodolite. There was actually much debate about bringing along a theodolite, as some felt the instrument was too delicate for the long, arduous journey. Both Lewis and Thomas Jefferson, however, believed that a theodolite was essential, and Jefferson (a former surveyor), offered to lend his own theodolite, which was created, as one might expect, by Jesse Ramsden.

Theodolites have changed much in the years since Lewis and Clark surveyed the Louisiana Purchase, and today’s theodolites are tough, durable instruments used for surveying, navigation, meteorology and a variety of engineering tasks.

At Warren Knight, we produce a wide range of theodolites, including telemetering theodolites, observation and pilot balloon observation theodolites, electronic mechanical meteorological theodolites and much more. We also can enhance a theodolite with video, PDA software, motor drives and custom optical systems. We also offer repair and servicing for all makes and models of theodolites.

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