What is the difference between magnetic and true north

This magnetic field is defined by intensity and two angles, inclination and declination. The relationship between geographic location and declination is something people using magnetic compasses have to consider.

Declination is the reason a compass reading for north in one location is different to a reading for north in another, especially if there is considerable distance between both locations. Read more: New evidence for a human magnetic sense that lets your brain detect the Earth's magnetic field. Bush walkers have to be mindful of declination. This difference can be significant. If a bush walker following a magnetic compass disregards the local value of declination, they may walk in the wrong direction.

This was significant as we learnt more about plate tectonics in the s, because it linked the idea of seafloor spreading from mid-ocean ridges to magnetic pole reversals. Geographic north, perhaps the more straightforward of the two, is the direction that points straight at the North Pole from any location on Earth. When flying an aircraft from A to B, we use directions based on geographic north. The three north are the True, the Grid, and Magnetic north.

The term Grid north is used in map projection to refer to the direction northwards along the grid lines in the navigation sector. True north geodetic north refers to the direction along the surface of the earth as you proceed towards the geographic North Pole. The Magnetic north refers to the direction a compass needle will point corresponding to the magnetic field lines of the Earth.

True north is measured in relation to the geographic North Pole and is generated as the earth rotates on its axis.

The direction is marked in our skies by the North Celestial Pole. The True north is seen to rotate in an arc in relation to stars for about 25, years to complete. Astronomers estimate that the Polaris will be closest to the Celestial North Pole around the years Grid north is a navigational phrase used to refer to the northward on a grid lines in a map projection. Grid north contrasts the true north and the magnetic north in that it is aligned to grid lines and always points upwards on a map.

If you have ever used a compass, you know it points to the north. But did you know it usually doesn't point to the geographic North Pole or to the magnetic North Pole? There are two main versions of north: true north and magnetic north.

There is also a third version, grid north, but this is not related to magnetic declination, so it is only briefly described at the bottom of this article. The difference between true north and magnetic north is called magnetic declination or magnetic variation. Some sources also erroneously refer to it as magnetic deviation.

It's essential to take this phenomenon into account when navigating with a compass. Find celestial objects in the sky. The magnetized needle of a compass usually does not point towards the geographical North Pole , or true north. Rather, it aligns itself with the direction of the Earth's magnetic field, showing magnetic north. In most locations on Earth, magnetic north differs from true north, so magnetic declination has to be taken into account.

Magnetic declination is expressed in degrees east or west. A western declination is usually stated as a negative value while an eastern declination is represented by a positive value. Trying to figure out a compass heading for the true-north directions shown in our Sun Calculator or Moon Calculator? Please see instructions below. The difference between true and magnetic north varies by location and over time. In most populated parts of the world, it currently ranges from 30 degrees west south-eastern tip of Africa to 26 degrees east southern tip of New Zealand.

However, most locations on Earth have a considerably smaller declination.