Evolution and Science of Indian Hindu and Other Calendars

About the BookThis book is about the evolution of different Calendar Systems from Sumerian to Gregorian and their logic, history, science. Many allied topics such as the eclipse, are explained, with real-life examples. Facts like, why a month has 28, 29, 30 or 31 days are explained with reasons and chronology. The book is a must also for all Indians, who will find answers to almost all queries regarding Indian and Hindu calendars. “A festival falling on different dates (of a Gregorian calendar) in different years is a common feature of all religions. For Hindus, the Holi Festival may occur on any day from March 1 to March 29; for Muslims, the Id may happen on any day of the year, whereas for Christians, the Easter Sunday may occur from March 22 to April 25,…” The author R. K. Chopra is a Mining Engineer, retired from the post of Director from a multi-billion dollar turnover company.   About the AuthorThe author, Rajesh Kumar Chopra hails from Varanasi, also known as Banaras and Kashi, the world’s oldest continuously inhabited city and India’s spiritual capital. His father Mr Dev Kumar Chopra, a science graduate, had a very good knowledge of Indian Astrology. From him, he learned about Indian constellations and Hindu Calendars. He studied some astronomy during his graduation in Mining Engineering from Banaras Hindu University in 1977, and worked in Tata Steel, Coal India Limited and Ministry of Coal, during which he travelled to many countries. He retired in 2015 from the post of Director Technical from a subsidiary of Coal India Limited. Since then he is engaged in various activities in the field of mining.   PrefaceI am a graduate of Mining Engineering from Banaras Hindu University. Sometime in 2008, I wrote an article on “The Science behind Indian (Hindu) Calendars”, which could still be found on the internet. The reason for writing was not much easy literature was available then. Hindu calendars are very scientific. Any layman even in the Jungle can easily tell the date by observing the sky. But the same cannot be said about the western calendars. But some confusion is generated at times when multiple dates are assigned for a Hindu festival. This happens because multiple calendar systems are being followed in this large country, India, with diverse traditions and cultures; and although each of them is based on its adopted principles, the difference is not easily understood due to the mingling of them over many centuries. A festival falling on different dates (of a Gregorian calendar) in different years is a common feature of all religions. For Hindus, the Holi Festival may occur on any day from March 1 to March 29; for Muslims, the Id may happen on any day of the year; whereas for Christians, the Easter Sunday may occur from March 22 to April 25, or as celebrated by some orthodox churches, from April 4 to May 8. This does not happen arbitrarily, but there is some logic behind this.