Marine Chronometer giving an accuracy of less than ±5 seconds per year,
( @ 35° longitude 5 seconds off is 1.18 miles @ 70° longitude 5 seconds off is 0.49 miles )
French Navy issued, 1980
Ships Marine Chronometer giving an accuracy of less than ±5 seconds per year
French Navy issued, 1980
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U.S. Navy quartermaster 3rd class, practices using a sextant as part of a navigation training aboard the amphibious assault ship USS Bonhomme Richard,
3rd class, practices using a sextant as part of a navigation training aboard the amphibious assault ship
Sextants can be read accurately to within 0.1 arcminutes, so the observer's position can be determined within (theoretically) 0.1 nautical miles (185.2 meters, or about 203 yards).
Most ocean navigators, measuring from a moving platform under fair conditions, can achieve a practical accuracy of approximately
1.73 miles , 1.5 nautical miles (2.8 km) or close to 1¾ minutes, enough to navigate safely when out of sight of land or other. hazards.
Note: The US Navy is within 5 miles for most navigators in WW2 and Armey Airforce was 25 miles at night. Only best was within 1½ miles From what I have read.
They also use dead reckoning so could explain the difference.
In WW2 the also used a sliderule too it is only 3 digits. The Navy did tried using a 12 foot silerule with more digits land base.
There for some Calculation for more accuracy they had book call Smoley's tables I have a FOUR COMBINED AKA 4 digit book. I know the had a 6 digit book too.
Down size to book is slow you look up every number and then add up everything
Dave