Rig Jyotishya Chapter 4 Paper 1 MA( astrology)

Rig Jyotishya:-

• This book was written somewhere 500 BC by sage Lagadha .Its highly significant in the history of Vedic science.
• By praying Prajapati (god of Pancha samvastara) and goddess saraswathi wrote this book.
• It was like a  manual  for determination of rituals and sacrifices by vedic Priests. It was like a social calendar for social and religious events.
• It provided Astronomical information that required for day to day life of people such as change of seasons, information for religious activities, stars of moon were mentioned to indicate days and days
• Mrigasira was called as agrahayana  ( beginning of the year) when sun was at vernal Equinox.
• Six ritus with 2 months each in a period of 12  solar months were given. It seems that in solar year there were 365 days (roughly).
• It was observed that moon came back to same position after 27 days based on 27 nakshatras.
• Starting Krittika, ending Vishaka 13 and half nakshatras in northen hemisphere called deva nakshatra and rest 13 and half are called Yama nakshatra.
• Winter season starts with  beginning of dhanista nakshatra when sun and moon moves (uttarayana) and summer would start with mid point aslesha (dakshinayana).
•  A yuga of Panchavastara  consists of 5 solar years and 67 lunar sidereal cycles. 1830 days and 1835 sidereal days. 1860 tithis
• 10 ayanas, 30 ritus
• Days are divided into  kastha, kalas, muhurtha, nadika
• I lunar nakshatra equals to 610 kalas
• Nakshatras are divided into 124 amsas.
• Day is divided into 60 Nadikas
• Each ritu has 61 days, each ayana 183 days
• Nakshatras are subdivided into Bhamsas
• Sidereal day corrections and there  were many mathematical calculations