@mavica in the beginning, there was no way of figuring out exactly where you were on the planet without being in sight of some landmark
you could work out your latitude by the angle of the sun measured on a sextant and an almanac of where it's meant to be on that day, but the longitude wasn't something you could work out
@mavica for centuries, the only way of finding your way across an ocean like the atlantic was to go north or south to the longitude you wanted, using the coastline to guide you to the right place, and then sailing due west or east and hope you hadn't gone off course too much
@mavica the theory was this: if you have a good reference of what the time is at your starting point, and a good sense of where the sun is where you are, then you can work out how far east or west of that starting point you are
you'd make a note of when the sun was at its highest where you are (that's called solar noon), and then compare it against what your clock says, the hours, minutes, and seconds between is how far east or west you are
@mavica this requires a very accurate clock, far more accurate than you could usually get at the time (badum tsh) but Harrison was a very good clockmaker
it took him years, most of his life in fact, but he eventually developed a clock that could do it
he called it the marine chronometer and it was the standard for navigation at sea since 1760-ish to when radio beacons were invented
@mavica oh yeah, this dude pulled it off in THE 18TH GODDAMN CENTURY and made a system that could locate you anywhere on the globe within like, 70 km
@mavica I won't pretend to know the full details, because this is somewhat beyond me, but he was using bimetallic strips as springs for temperature compensation, caged roller bearings, all of this is stuff still used today in watchmaking
oh, and he made it look good as well, dude was just fucking styling on people at this point
@mavica he had a hard time getting paid the prize money though
remember that celestial method that people were trying to make work earlier?
yeah, the main dude pushing that idea was on the panel that determined if anyone won the prize, and he was very miffed that this carpenter had managed to solve the problem before his celestial method could
@mavica oh yeah, Harrison wasn't trained as a watchmaker
he was trained as a carpenter, and just went and made massive breakthroughs in horology and navigation
@mavica and that's pretty much all I remember off the top of my head about that early stuff
there's a book called Longitude by Dava Sobel which is an excellent read about all this
@mavica clocks at the time were primarily of the standing up in your hallway sort, pendulum clocks, any movement of the case would put the clock off by a fair amount per day which, if you're on a boat is not ideal
and so a bloke called John Harrison, a prodigy of a clockmaker, decided to try to build a clock with a lever escapement that would be accurate enough to tell the time at sea