The main principle behind the timing of namaz is based on the relation between the earth and sun. For example zuhoor means that time of the day when the sun is directly above the earth/land and it is around 12:15pm according to the university of Islamic Sciences Karachi and we can pray at this time. But the azaan is often around an hour late, so what was the original purpose of azaan if one can just see the sun and predict or in today’s world we can consider google. So why was azaan introduced