Longitude

[Dan_Shade]

I watched a BBC documentary on longitude a while back, ironically called "Longitude", it's an interesting story of how England encouraged citizens to solve the longitude problem.  Basic methods involve time or celestial bodies.

Shadows are shortest at solar noon.  Earth turns 15° every hour, so you can determine your latitude based on the time difference from Greenwich, England at solar noon. The 0° meridian is in Greenwich.

I did an experiment last week using a tripod, a plumb bob, and a knot, measuring every few minutes to find the shortest shadow.


The shadow distance was shortest at around 1:19 pm, DST/12:19 pm EST.  Which is 5:19 from Gmt (Greenwich Mean Time).

I calculated my longitude to be -79.74°, Google maps said I was at -79.46°. I calculated my location to be 15 miles further west. I was impressed, my tools were very crude.

[Nebraska]

That was interesting.  Thanks 

[barbender]

That's cool 👍

[Plankton]

Wow super cool! Amazing what you can do with a few sticks and some knowledge.

[Stephen1]

That is pretty cool. amazing that this info does not change even after centuries of time. 

[SwampDonkey]

Cool stuff.  A regular Prof. Julius Sumner Miller.  'What makes it so?' 

You'll get a kick out of the old fart. Here's one video, but there's many

https://www.youtube.com/watch?v=4wa8IKMYwK8&t=53s