Diwali Connection with Astronomy – Amateur Astronomers Association

Truth be told, it is human to look up at the night skies and wonder if the movement, presence or absence of certain objects mean something to the terrestrials looking at them. There are several parallels in cultures around the world. Though the Indian civilization happens to be one of the earliest and oldest, it is thus interesting to see how the math and knowledge that was passed down orally had only very small errors considering the precision we have today.

There are three phases in the evolution of how humans viewed what they saw in the skies above:

– Propitiatory phase: sky was seen as home to capricious divinities to be feared and propitiated.

– Negotiatory: humans noticed patterns in behavior of divinities and started to employ a negotiatory approach.

– Galilean: which is the phase we live in today.

Orbits of the seven geocentric planets (graha) by virtue of their predictability represented cosmic order, while phenomena like meteors, comets and eclipses which did not fit into any pattern were classified as utpata, portent or calamity.

Ritual was a means of securing divine approval and support for terrestrial actions. To be effective, the ritual had to be elaborate and well-timed, so that a careful distinction could be made between auspicious and inauspicious times. Since planetary motions provided a natural means of time keeping, their refined study became important.

The Siddhantic calendar, the basis of all Hindu rituals, uses a lunar month. It is a fascinating living document because its elements have been calculated orally for 1,500 years. Each Siddhantic month has 30 tithis, “days” of unequal duration. Since 12 lunar months make only 354 days, for every 30 months an extra month is added in the Siddhantic calendar.

The last full moon of a Siddhantic year is celebrated as Holi. The new year is ushered in with a nine-tithi Navratri I, ending in Ram Navami. Six months later comes Navratri II, heralding the month of Ashvina, which contains the vernal equinox. The eighth and ninth tithis of Navratri II are dedicated to Durga. The next tithi is Dussehra. The new moon following Dussehra is Diwali. This is how Diwali is observed and celebrated.