Knowing the difference (measured in angular degrees) between true north and the horizontal trace of the magnetic field for your location allows you to correct your compass for the magnetic field in your area. This angular difference is called your declination.
What is the purpose of declination?
At most places on the Earth’s surface, the compass doesn’t point exactly toward geographic north . The deviation of the compass from true north is an angle called “declination” (or “magnetic declination”).
What is declination and why is it important?
When navigating with a map and a compass, it is important to understand that the true or geographical north (North Pole) is not the same as magnetic north . The angle between true north and magnetic north is called declination and is either east or west of magnetic north depending on where you are on Earth.
What is magnetic declination used for?
The magnetic declination at any particular place can be measured directly by reference to the celestial poles —the points in the heavens around which the stars appear to revolve, which mark the direction of true north and true south. The instrument used to perform this measurement is known as a declinometer.
How do you use declination in a sentence?
Up to this time, Venus has had a superior declination to the Sun. The number 13.50 happens to be the magnetic declination for this area. We are currently enjoying this planet close to its maximum northern declination at a time when the ring system is wide open.
Does declination mean decline?
Declination can mean a bending or sloping downward . ... A declination can also be a polite refusal, especially in a formal or official situation. In this sense, it is a noun form of the verb decline, meaning to refuse or to turn something down.
Why is true north so important?
When we use a map and compass to navigate, we are actually using true north to determine our direction of travel ; however, if we just follow our compass needle, it will eventually bring us to magnetic north.
What does a declination of 0 mean?
North declination is considered positive and south, negative. Thus, +90° declination marks the north celestial pole, 0° the celestial equator , and -90° the south celestial pole. The usual symbol for declination is the lowercase Greek letter δ (delta).
What two things does the Earth’s declination affect?
The two tidal bulges track the changes in lunar declination, also increasing or decreasing their angles to the equator. Similarly, the sun’s relative position to the equator changes over the course of a year as the Earth rotates around it. The sun’s declination affects the seasons as well as the tides .
What does declination mean in law?
5a : a formal refusal . b law : a decision by a prosecutor not to pursue an indictment. 6 : the angle formed between a magnetic needle and the geographical meridian.
Should I use true north or Magnetic North?
True north, which is a GPS bearing linked to the geographical location of the North Pole, works when Location Services is turned on. Magnetic north , on the other hand, depends on the Earth’s natural magnetism, which changes based on your physical location. It works when Location Services is both on and off.
What is the cause of magnetic variation?
Magnetic declination is caused by the complex shape of the Earth’s magnetic field . Magnetic declination refers to the use of a compass with its needle...
How do you solve magnetic declination?
The angle between grid north and true north is called the convergence angle. To obtain the true declination it is necessary to add or subtract the convergence angle to the Grid Declination .
What is angle of declination for Earth?
If the Earth were not tilted on its axis of rotation, the declination would always be 0° . However, the Earth is tilted by 23.45° and the declination angle varies plus or minus this amount. Only at the spring and fall equinoxes is the declination angle equal to 0°.
What is called declination?
The deviation of the compass from true north is an angle called “declination” (or “magnetic declination”). It is a quantity that has been a nuisance to navigators for centuries, especially since it varies with both geographic location and time.
What is declination diagram?
A declination diagram is ‘... a diagram that shows the angular relationship, represented by prongs , among grid, magnetic, and true norths... ... Declination diagram showing relations among true, grid, and magnetic north reference lines on the Madison West, Wisconsin, USGS 1:24,000 quadrangle.
