Nirayana Sauramana - a Solar Calendar
In the past, we saw that
Nakshatra defines the moon's position in the sky.
Just as we divide the sky into 27 parts
to define the moon's position,
we can divide the sky into twelve parts
to define the sun's position.
With respect to this twelve part sky,
the sun stays in each part for a month.
In month 1 it would be around a group of stars.
In month 2 the sun would shift to the next group east of us.
In month 13 it would be around the same group of stars
as that of month 1.
Thus, we calibrate the moon's position in the sky each day,
while we calibrate the sun's position in the sky every month.
This twelve part division of the sky is called Rashi (Zodiac).
Each of the twelve Rashi names correspond to a part of the
sky identified by a group of stars.
The sun's movement across the Rashi defines the
Nirayana Sauramana (Solar) calendar.
This calendar is followed in the
Tamil & Malayalam traditions. I am told this
calendar is also followed by the Bangala tradition.
When we say "follow", it means this Sauramana calendar
is used as the primary calendar. However, many special
days like Rama Navami, Siva Ratri, etc. are based
on the Chandramana (Lunar Calendar).
Special days like Makara Sankaranti,
Karadaya Nombu (coming up next week)
are observed based on Nirayana Sauramana calendar.
Then there are special days where parameters from
both the calendar are considered, to observe the day.
e.g.: Karthigai (very specific to Tamil tradition) is
observed on the Purnima (a Chandramana parameter)
of the month of Vrishchika (a Sauramana parameter).
So each of the two calendars are used based on context.
In the Nirayana Sauramana calendar, a new month is marked
by the sun moving from one of the twelve parts to the next.
This is called Sankramanam or Sankaranti.
So, Makara Sankaranti is when sun enters Makara Rashi.
In Samskritam, the name of the month is the Rashi name.
So when we say the month is Makara, it
means the sun is in that area of the sky defined by
the group of stars called Makara Rashi.
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