Give definition of magnetic declination. How does the declination vary with latitude ? Where is it minimum ?

tion:True north (also called geodetic north) is the direction along EARTH's surface towards the geographic North Pole or True North Pole.Geodetic north differs from magnetic north (the direction a compass points toward the Magnetic North Pole), and from GRID north (the direction northwards along the grid lines of a MAP projection). Geodetic true north also differs very slightly from astronomical true north (typically by a few arcseconds) because the local gravity may not POINT at the exact ROTATIONAL axis of Earth.The direction of astronomical true north is marked in the skies by the north celestial pole. This is within about 1° of the position of Polaris, so that the star would appear to trace a tiny circle in the sky each sidereal day. Due to the axial precession of Earth, true north rotates in an arc with respect to the stars that takes approximately 25,000 years to complete. Around 2100–02, Polaris will make its closest approach to the celestial north pole (extrapolated from recent Earth precession).[1][2][3] The visible star nearest the north celestial pole 5,000 years ago was Thuban.[4]