For an explanation, see the main splats page
The principles of navigation
- Navigation is the art of knowing where you are on the surface of the globe. It is an ancient art that has largely been replaced with technology in recent times.
- As late as the 20th century, celestial navigation relied on the observer being able to see the sun, the moon, or stars at exactly the right time.
- Latitude can be measured by taking sightings on the sun or stars, although it is mostly done today by GPS hardware that relies on the locations of satellites.
- Simple interference in the form of fog, cloud, mist, or being busy when deciding was to be taken, could cause a 24-hour delay in getting an accurate position.
- Longitude can be measured best with a good chronometer, so you can relate your present position to the reference position from which longitudes are measured.
- Longitude may also be measured by careful observation of the moon and using tables, but this is an unreliable method, especially when a ship is moving.
- In 1735, John Harrison built his first marine chronometer (Number One), designed to win the award of the British Board of Longitude for an accurate time keeper.
- In 1759 John Harrison completed his fourth chronometer (Number Four), which would eventually gain him the Board of Longitude's prize for accurate time keeping.
- In 1761 John Harrison's portable chronometer (Number Four) was successfully tested on a trip from Britain to the West Indies and back, proving itself at sea.
- The quadrant was an early navigational instrument with limited use.
- The sextant was an early navigational instrument with limited use, but it was able to give remarkably accurate results when latitude needed to be found.
- A compass is needed to make sure a boat sails in the right direction, once it is out of sight of land, although radar and GPS equipment are more reliable.
- One of the drawbacks of the old magnetic compass was that it tended to swing around when used on a small rocking boat. Oil damping fixed this.
- One of the drawbacks of the old magnetic compass was that it relied on a magnetic field that was not uniform in its direction from place to place.
- Edmond Halley experimented with the use of charts of magnetic deviation, the difference between true and magnetic north, to find longitude around the world.
- Between 1783 and 1824, the national Ordnance Survey of England, mapped all of Britain, except for the eastern part of England and north-west Scotland.
- The main role of the people we call Australian explorers was to work across Australia, surveying the series of triangles to map the continent by triangulation.
This file is http://members.ozemail.com.au/~macinnis/scifun/splatsnavig.htm, first created on February 19, 2008. Last recorded revision (well I get lazy and forget sometimes!) was on February 19, 2008.
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