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The diagram illustrates four possible combinations. This requires a coordinate transformation. They are referred to the equinoxes instead so use sin instead of cos. The declination of the sun is the angle between the equator and a line drawn from the centre of the Earth to the centre of the sun. The first known determination of magnetic declination was made by the Chinese in about 720 AD. Declination charts have been produced on a regular basis ever since. For 1590 to 1900 the calculator is based on the gufm1 model. Learn how to use the magnetic declination with a compass. However, the Earth is tilted by 23.45° and the declination angle varies plus or minus this amount. The declination angle, denoted by δ, varies seasonally due to the tilt of the Earth on its axis of rotation and the rotation of the Earth around the sun. The declination calculator is a simple an easy way to calculate up-to-date declination for any location on Earth. Simply enter the Year, Latitude and Longitude of your location and the declination calculator will give you the declination based on the latest magnetic reference field models. The declination angle can be calculated by the equation 1: where d is the day of the year with Jan 1 as d = 1. A compass lines up with the horizontal component of the magnetic field in a direction called magnetic north. the PSA algorithm below) is up to 1°. Changes in declination become increasingly irregular in both amplitude and frequency as one approaches the North Magnetic Pole, a result of the weak horizontal component of the magnetic field. The declination angle can also be defined in other ways. Mean annual change decreasing 11.5. The grid convergence angle is also supplied when grid declination is selected. In the equation above, the +10 comes from the fact that the winter solstice occurs before the start of the year. On the other hand, at Ottawa, the yearly change in declination is almost zero. Four cases are illustrated: Declination is also shown on aeronautical charts as contour lines and on hydrographic (marine) charts either as contour lines or in the form of a compass rose, depending on the scale of the chart. Choose North or South, East or West from the 'radio' buttons. Degrees and minutes, e.g. If you have ever used a compass, you know it points to the north. It can be seen that in Southern Canada users of such compasses will seldom experience fluctuations larger than 2 degrees. The declination calculator is a simple an easy way to calculate up-to-date declination for any location on Earth. When entering the geographic latitude or longitude use one of the following three conventions: Grid Declination is defined as the angle of magnetic North relative to grid North where grid North is referenced to the grid lines shown on navigation charts with a Tranverse Mercator projection for a UTM coordinate system. Maps of the Earth's magnetic field are available from the National Geophysical Data Center of the National Oceanic and Atmospheric Administration : http://ngdc.noaa.gov/wist/magfield.jsp. Beneath the diagram is a statement informing the user about the annual change of declination. If the Earth were not tilted on its axis of rotation, the declination would always be 0°. Thus the simpler equation is preferred since it is equally accurate. However, because of the complex shape of the Earth's magnetic field there are few places where a compass needle will point exactly north. However, the Earth is tilted by 23.45° and the declination angle varies plus or minus this amount. Here is an explanation of the differences between the three terms. For this calculator, latitude is positive to the NORTH, and longitude is … The diagram shows the percentage of days in a typical year during which magnetic declination will fluctuate by more than a given amount from its normal value. This is not true; if you follow your compass needle you will eventually arrive at the North Magnetic Pole, but not by the most direct route. Therefore Declination in 2003 is: It is important to remember that the annual change does not remain constant with time. The seasonal variation of the declination angle is shown in the animation below. This angle is properly called grid declination. The angle between grid north and true north is called the convergence angle. The derivation of the declination angle assumes a circular orbit and gives the following result: $$sin\ \delta=\sin{\left({-23.45}^0\right)}\cos{\left[\frac{360}{365}\left(d+10\right)\right]}$$. However, someone on a canoe trip in the NWT would find his or her compass in error by more than 2 degrees on more than 1 day in 4. 45 54 3.3. Only at the spring and fall equinoxes is the declination angle equal to 0°. The angle between magnetic north and true north is called magnetic declination.