The sun radiates energy equally in all directions. The rays spread out from the core to the outward direction. The distance between the two rays increases as they go further away from each other and they appear to be parallel. In practice, the rays are considered to be parallel to each other with the same intensity.
Latitudes, Longitudes and Hemispheres:
Latitudes: Latitudes are imaginary lines on the surface of Earth, which are perpendicular to the axis passing through ‘The North Pole’ & ‘The South Pole’. Latitudes are parallel to each other. Latitudes are used to define the position of a place on the surface of the earth with respect to the distance from the equator in Northern and Southern hemisphere.
Longitudes: Longitudes are imaginary lines on the surface of Earth, which are perpendicular to the Latitudes. They are radial giant circles passing through the North & South Poles. Longitudes are used to define the difference in time zones.
Equator: The imaginary line at the exact half distance between The North Pole & The South Pole is assumed as 0°. It is also called The Equator.
Prime Meridian: A prime meridian is a meridian in a geographic coordinate system at which longitude is defined to be 0°. Together, a prime meridian and its anti-meridian form a great circle. This great circle divides a spheroid into two hemispheres. It passes through Greenwich, a part of London in the United Kingdom.
Northern Hemisphere: The hemisphere from the Equator to North pole is called The Northern Hemisphere.
Southern Hemisphere: The hemisphere from the Equator to South pole is called The Southern Hemisphere.
Eastern Hemisphere: The hemisphere to the east of the Prime Meridian is called as the Eastern Hemisphere.
Western Hemisphere: The hemisphere to the west of the Prime Meridian is called as Western Hemisphere.
Altitude: The angular distance of any point of the celestial sphere, measured from the horizon, on the great circle passing the body and the zenith. Or The distance of an object that appears to be above the horizon. The angle is measured up from the closest point on the horizon. The apparent position of the sun with respect to the time starting from sunrise to noon to sunset is measured as the Altitude.
Azimuth: The angle measured between meridians passing through the North point and the point in question. Or it is the angular distance along the horizon to the location of the object. By convention, azimuth is measured from the north towards the east along the horizon. Earth’s axis of rotation is tilted by 23 1/2 degrees. Because of this, we feel that the apparent position of the sun appears to be inclined towards the South and North. Azimuth is important to determine the position of the Sun.
Sun path: Sun path, sometimes also called day arc, refers to the daily and seasonal arc-like path that the Sun appears to follow across the sky as the Earth rotates and orbits the Sun. The Sun’s path affects the length of daytime experienced and amount of daylight received along a certain latitude during a given season.
Let us find out the apparent position of the sun at noon 12 on 21st June and 21st December at Nashik if the coordinates of Nashik are 20°N and 73.78°E.
At the Equator:
The axis is tilted by 23.5° to North and South. Because of the tilt, the Sun does not appear to be exactly over the top your head at noon on all days. At 12 noon on June 21st, the position of Sun appears to be tilted towards North by 23½°.
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