Equation of time: The time within which a place is rotated on the axis in one complete rotation and then comes back to the same position, so that the sun begins to shine above it, is called a Solar day. But the Earth’s orbit is not circular, but it is elliptical. At the same time, the position of the Sun is not centered. As a result the earth reaches. When there is winter season in the Northern Hemisphere, then the Earth is relatively close to the Sun, which is called Perihelion.
On the contrary, when it is summer in the northern hemisphere, the Earth is relatively far from the Sun and we call it Aphelion. It is worth noting that the change of the seasons does not depend on the distance of the sun. It is related to the height of the sun’s in sky. i.e. the angular position of the rays obtained and the thermal power obtained from them. When the earth is in a perihelion state, As revolution speed becomes faster. In contrast, the period of Solar – Day (the time between two actual position) decreases – So two types of time are experienced.