Subject: I have found a DVD that I think you would enjoy
|NOVA Lost at Sea - The Search for Longitude|
Actor: Richard Dreyfuss
Genres: Special Interests, Television, Educational, Documentary
Before global positioning systems, modern map making even before America was America the concept of longitude was just a dream. Without its guidance, navigation in the 1700s was both unpredictable and deadly...until one ma... more »
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John Harrison, Father of Longitude
I. Chiang | Silicon Valley, CA, USA | 02/13/2008
(5 out of 5 stars)
"It seems to be trivial to know where you are, especially when the era of GPS (global positioning system) starts in 1995. It is, however, a challenge to know this at sea in the 1700s. Although one can tell the latitude by measuring the angle of the sun at noon, there is no practical way to know the longitude at that time. This makes navigation unreliable and deadly.
Most people, including Isaac Newton, think this problem must be solved by astronomers, or professors in famous universities by measuring the stars or the moon. It is John Harrison, an unschooled carpenter and watchmaker from the country, to get this job done and win the 20,000 pounds (millions in today's dollars) by his custom-made clock.
The key to know where you are is to know what time it is. This is still the principle that GPS works today. The clocks in GPS are atomic. However, the clocks then are mechanic and are very difficult, if not impossible, to maintain its precision at sea due to the shaking of a ship. In addition, the gravity, temperature and friction are also factors to make a clock imprecise when traveling a long distance. Finally, it took John Harrison 58 years to overcome all these and make longitude predictable at sea.
What we think straightforward may go through long struggles. What we think a reasonable and better idea may turn out impractical. It is fun to learn the above while watching this film. And it would be good if more people know about this history."
Typical NOVA - Excellent
rsb | Vienna, WV | 10/06/2008
(5 out of 5 stars)
"This is a super dramatization and historical account of the sometimes less than scientific search for a way to find longitude at sea.
The video is beautifully produced and the acting is great. The science is accurate and engaging for all levels of understanding.
Harrison's genius is expertly portrayed and his contribution to the scientific method is well documented. The prejudice of the so-called learned academics against the practitioner is a reminder that we can still miss the boat with preconceptions.