How to calculate the location of the sub-solar point?

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The sub-solar point is the point on the Earth's surface where the sun appears at its highest point in the sky at any given time. It changes constantly due to the Earth's rotation and position in its orbit around the sun. Here are the steps to calculate the location of the sub-solar point:

1. Determine the current time and date in UTC (Coordinated Universal Time).

2. Find the declination of the sun. This is the angle between the plane of the Earth's equator and the plane of the sun's apparent path in the sky. The declination changes throughout the year due to the Earth's tilt on its axis. You can find tables or calculators online that will give you the sun's declination for a given date.

3. Find the solar hour angle. This is the angle between the sun's position in the sky and the noon meridian (an imaginary line running from due north to due south through the observer's position) at the given location. You can calculate this using the equation: SHA = 15° x (Local Standard Time - 12), where SHA is the solar hour angle and Local Standard Time is the time in hours ahead or behind UTC at the given location.

4. Calculate the latitude of the sub-solar point. The latitude is equal to the current declination of the sun minus the solar hour angle, divided by 2. This gives you the latitude of the sub-solar point in degrees.

5. Calculate the longitude of the sub-solar point. This is the difference between the current Greenwich Mean Time (GMT) and the Local Mean Time (LMT) at the given location, multiplied by 15 (since each time zone is 15 degrees wide). This gives you the longitude of the sub-solar point in degrees.

6. Use the latitude and longitude to determine the location of the sub-solar point on a map or globe.

Note that this calculation assumes a perfectly spherical Earth and may not be completely accurate due to factors such as atmospheric refraction and the Earth's elliptical orbit.