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A magnetometer is a device that measures magnetism. Magnetometers can accurate measure magnetization, strength and direction of the magnetic field around them. The first magnetometer was introduced by Carl Friedrich Gauss in 1833. They are today used in an incredible variety of devices, including mobile phones.
A gyrocompass is a type of non-magnetic compass which use a fast-spinning disc and rotation of any planetary body to automatically find geographical direction. A gyrocompass is a device that revolutionized naval shipping after modern sailors noticed that metal hulls of their ships interfered with the magnetic field that was detected by their ship's magnetic compasses. However, even though they were initially created for naval use, gyrocompasses today have much more uses.
The solar compass is a precision surveying instrument that makes use of the sun's direction that allows surveyors to determine the true north direction by reference to the sun. Sun compass was first invented and patented by William Austin Burt on February 25, 1836.
Compasses can be divided on those that direct to the magnetic poles of Earth and those that direct to true poles of Earth. There are also compasses that are used professional, amateur and even religious purposes. Read more about types of compasses.