Indian festivals have an astronomical basis. For this reason, one can move the clock back, and study festival dates even during the pre-historic era. Besides, we know that Shiva worship was prevalent in Indus Valley civilization. We know this from clay seal artifacts from that period. When did Shivaratri, a popular festival related to Shiva occur annually? What was the season, the time of the year and the night sky configuration at that time. It is an interesting exercise to find this information.
Now a days, Shivaratri occurs in late February or early March. In the month of March, the full moon falls in the Magha Nakshatra region of the sky. Nakshtras are the equal divisions through which the planets move in the sky. There are 27 Nakshatras. Shivaratri day coincides with the 13th phase of the waning moon in the month of Magha. Shivaratri is on Feb 27th in 2014 which is two months after the winter solstice. How far was Shivaratri from winter solstice* five thousand years ago? Anyone can use planetarium software and find this answer today.
K.D Abhayankar, an Indian astronomer analyzed the Shivaratri which occurred just two days before the winter solstice in the year 3104 BCE. As is usual for this day. the crescent moon was visible in the Eastern sky right before the sunrise. But the eastern sky also presented a rare sight! Four planets, namely Mars, Saturn, Jupiter and Venus were in close proximity. The planet mercury too was in close proximity but was invisible as it rose after the sunrise that day.
Winter Solstice Ritual
Winter solstice was an important event during Vedic times. This was for the reason that it marked the start of the year long Savana* fire ritual. A sight of Shivaratri moon and the Sun being accompanied by planets in the eastern horizon is rare. This would have been a unique way of welcoming the new Savana year for the Vedic people. Kali Yuga era started two years later, on Feb 17th 3102BCE. On that day, the Sun and the Moon jointly arose in the eastern horizon, at the 1st point of Aries. The present era indeed started with a planetary alignment of a cultural significance. Therefore, prominent astronomers, such as Aryabhata, refer to an alignment at the start of the Kali era. However, most translators of Indian astronomical text misunderstand this to be a reference to a perfect planetary alignment! “Ancient Skies and Astronomy Now” presents a viewpoint which most popular translations of Vedic texts ignore.
* Winter Solstice shifts back a month in ~2000 years.