# What are the Mathematical Algorithms/Formulas behind hindu Sunrise and Sunset Calculations? [closed]

There are differences between Astronomical Sunrise/Sunset calculation and Hindu Sunrise/Sunset calculations. The astronomical algorithms to calculate the sunrise/sunset can be found over the internet. Here is a calculation that I followed to correctly calculate the astronomical sunrise/sunset time.

Sunrise and Sunset algorithm

Hindu sunrise/sunset is considered when the center of the Sun disk is at the horizon, also the refraction effect must be considered.

Hindu Sunrise = Astronomical Sunrise + Time taken by the Sun to rise half of its diameter + Time taken by the Sun to rise further to neutralize the refraction effect.

Similarly, Hindu Sunset = Astronomical Sunset - Time taken by the Sun to set half of its diameter - Time taken by the Sun to set further to neutralize the refraction effect.

I am able to derive the Astronomical Sunrise/Sunset, but how to do the calculation for the following?:

1. Time taken by the Sun to rise half of its diameter.
2. Time taken by the Sun to rise further to neutralize the refraction effect.
3. Time taken by the Sun to set half of its diameter.
4. Time taken by the Sun to set further to neutralize the refraction effect.

I need some enlightenment on the above question. Any help with the algorithms/forumlas or resources will be highly appreciated.