What is zero shadow day? Unique celestial event set to grace Bengaluru on Aug 18

Zero shadow day is a rare celestial phenomenon which will be witnessed in Bengaluru on August 18. Every year on the zero shadow days, students and astrophiles who are located between the two Tropics erect vertical poles, and different objects and sometimes even stand outside to see for themselves the cosmic event. These two days are called zero shadow days.” Moreover, according to the Astronomical Society of India, people living between +23.5 and -23.5 degrees latitude Sun's declination will be equal to their latitude twice a year. It is measured with 180 imaginary lines that form circles around Earth east-west, parallel to the Equator.’ When did Bengaulur experience zero shadow day before August 18? Bengaluru had earlier observed Zero Shadow Day in April this year when all vertical objects in the city became shadow-less for a short period of time at 12.17 pm.