Featured posts
What is the National Ship Register?
Customs management in the Canary Islands
Type of containers used in maritime transport
Controlling the eclination or magnetic deviation on a nautical chart is essential in order to avoid losing the course in navigation. To do this, it is necessary to take into account a series of notions and basic knowledge related to cartography, topography and the Earth’s magnetic field, among which are the normal changes that occur in a more or less constant way.
Know what magnetic declination is
The magnetic declination is the angle between the geographic north and the magnetic north, since the two are not located in the same area, but they do have a certain proximity. This angle varies over the years and also varies depending on where we are, it is not the same in all places. Therefore, it is necessary to establish certain parameters to calculate it.
Geographic north pole
The geographic north pole is the one we all know. It is, together with the geographic south pole, one of the points on the earth’s surface that coincides with its axis of rotation. The earth rotates around itself on this axis. At present, there is no land mass in this area, there are only blocks of ice; however, at the geographic south pole, lies Antarctica. Millions of years ago the continental configuration was different due to continental drift and plate tectonics.
Magnetic north pole
The magnetic north pole is measured by compasses and depends on the earth’s magnetic field. This magnetic field is generated at the core of our planet, consisting mainly of iron and nickel, and varies over time. There are geological records that speak of important inversions in the magnetic field caused by variations at the Earth’s core. Thus, the magnetic north almost never coincides with the geographic north, which means that, if these differences are not corrected, the compasses will not point to the “real north” of the Earth. And this is what magnetic declination corrections take care of.