Determine Longitude

This video demonstrates how to use observations of the sun combined with local and Greenwich time to determine longitude. An interesting project for anyone interested in navigation and the geometry of our relationship with the sun.

[iamcarbonandotherbits.]

John Harrison was a cabinet maker by trade, so not only was he not taken seriously by the admiralty but he also had to teach himself the intricacies of working with metals and all the tolerances that went with it. A truly amazing master of his time. Pun not intended.

[johnmcclain]

I've done these calculations since my childhood as a Boy Scout and this has been the best, clearest explanation of the exactness of solar timing I've ever come across. Very nice, simple, and exact. Thanks!

[peterfeltham]

This gentleman is a very good narrator and explained his subject so well. His speech is clear and evenly paced, well done.

[robertbonsai]

My 4x great grandfather was first surveyor hire by Hudson’s Bay company in late 1700’s. His work has been verified to e a few degrees off. A ocean away in a raw country, just a sextant and mercury as a mirrors and all math done by hand. It would take him up to six hours for just one point. Wow. His story can be told I. Book, Mapmaker, good read.

[itskittyme]

I watched 3 youtube videos with young youtubers who were only yelling and joking, not explaining it properly.
Now I finally found this video and I can finally understand it, thanks for that!

[PacoOtis]

Excellent video! Thank you very much! As a septuagenarian retired pilot I was able to see many advances in navigation aids and always appreciated our predecessors and what they went through. You've really made appreciating their knowledge and efforts easier to grasp. Again, thanks!

[trueopsimath]

A very well-illustrated explanation for determining longitude. This former sailor approves!

[robinj.]

I had to Teach myself Celestial Navigation. After stumbled through half a dozen different books, which were little help, I finally found George Mixter! His book: "Primer of Navigation" from 1940 explained everything in clear, practical terms. And I've been a Wiz ever since!

[DIYivan]

Thanks for putting this together! I’m a surveyor and these days we use positional data provided by computers. I can’t wait to try this out and do some “real” old school surveying.

[Mytyweav]

I totally enjoyed this video... At almost 69 years of age, I finally have a pretty damn good idea how all this is measured/calculated. Thank you very much!

[condensermike]

Glad I found this channel. Simple, not over produced, and spot on. Well done!

[mrguy]

Excellent video, thank you for the demonstration and animations.
There is one thing I would add - how to determine your time zone.
Your marine chronometer would be set to Greenwich time. Therefore wherever you are, you only need to take the time of solar noon, calculate the difference from 12:00pm, and then multiply by 15 degrees. I.e. the clock tells you your time zone.

[jeffcampsall]

Finally, a proper and clear description of calculating longitude. Going through all the other sites and videos on this subject has been unbelievably painful. Thank you !

[ianmcculloch]

I love the story of John Harrison and his clock, his discovery and how he had to beat his detractors. This presentation is very enlightening, thank you.

[RasheedKhan-hexx]

Fascinating. In the movie Jeremy Irons plays the guy who had to restore Harrison's clock. He discovers it was like navigating a maze. Apparently whenever Harrison tried something which didn't work, he didn't undo it and try something else, instead he built a new mechanism to overcome the problem created by the first. So layers and layers of complexity were built up one on top of another. Is it a coincidence that watchmakers still call additional mechanical features "complications"?

[guitarlover]

This is one of the most interesting videos that I have ever seen. Very well explained. Thank you!

[robertbilling]

That's remarkable accuracy for such simple equipment. Well done!

[vassilenaduleva]

Great video. To those interested in John Harrison’s story the man who invented the maritime timekeeper watch this period movie called Longitude 2000 UK movie. Brilliant acting brilliant telling of inspiring story of resilience

[michaelodonoghue]

I spent 20 Years teaching Navigation. Once asked a guy to tell Me where We were. After a few Minutes of studying his Map and Compass he pointed to a slight rise in the ground a few Metres away and Proudly Announced "We're over there".

[Colombo]

Thank you. This is one of the most outstanding presentations I have watched on YouTube: crystal clear, word perfect, a joy to watch! It is amazing what a gifted, intelligent teacher can achieve!