Marine chronometer - Video Learning - WizScience.com
A "marine chronometer" is a timepiece that is precise and accurate enough to be used as a portable time standard; it can therefore be used to determine longitude by means of celestial navigation. When first developed in the
18th century, it was a major technical achievement, as accurate knowledge of the time over a long sea voyage is necessary for navigation, lacking electronic or communications aids. The first true chronometer was the life work of one man,
John Harrison, spanning 31 years of persistent experimentation and testing that revolutionized naval navigation and enabling the
Age of Discovery and Colonialism to accelerate.
The term "chronometer" is used more recently to describe watches tested and certified to meet certain precision standards. Timepieces made in
Switzerland may display the word 'chronometer' only if certified by the
COSC .
To determine a position on the
Earth's surface, it is necessary and sufficient to know the latitude, longitude, and altitude.
Altitude considerations can, of course, be ignored for vessels operating at sea level. Until the mid-1750s, accurate navigation at sea out of sight of land was an unsolved problem due to the difficulty in calculating longitude.
Navigators could determine their latitude by measuring the sun's angle at noon or, in the
Northern Hemisphere, to measure the angle of
Polaris from the horizon . To find their longitude, however, they needed a time standard that would work aboard a ship.
Observation of regular celestial motions, such as
Galileo's method based on observing
Jupiter's natural satellites, was usually not possible at sea due to the ship's motion. The
Lunar Distance Method, initially proposed by
Johannes Werner in 1514, was developed in parallel with the marine chronometer.
The Dutch scientist
Gemma Frisius was the first to propose the use of a chronometer to determine longitude in 1530.
Wiz
Science™ is "the" learning channel for children and all ages.
SUBSCRIBE
TODAY
Disclaimer: This video is for your information only. The author or publisher does not guarantee the accuracy of the content presented in this video.
USE AT YOUR
OWN RISK.
Background Music:
"
The Place Inside" by
Silent Partner (royalty-free) from YouTube
Audio Library.
This video uses material/images from https://en.wikipedia.org/wiki/
Marine+chronometer, which is released under
Creative Commons Attribution-Share-Alike
License 3.0 http://creativecommons.org/licenses/by-sa/3.0/ . This video is licensed under Creative Commons Attribution-Share-Alike License 3.0 http://creativecommons.org/licenses/by-sa/3.0/ . To reuse/adapt the content in your own work, you must comply with the license terms.