<p>Precession of equinoxes means that the North pole of the Earth is changing its direction. This also means, that the dates of the seasons (seen from outside the Solar System (= sidereal)) are changing. <em>Nirayana</em> calculates the date of Makar Sankranti with adding years to the first Makar Sankranti, but <em>sayana</em> calculates the date of Makar Sankranti relative to stars (sidereal).</p>
<p>In a nutshell: <em>nirayana</em> is on the same <em>date</em> as the first event (first Makar Sankranti), but <em>sayana</em> is on the same <em>event</em> as the first Makar Sankranti (winter solstice). Yes, winter solstice was once on the 14 January.</p>

CC BY-SA 4.0
2020-12-20T21:23:43.637Z
2020-12-20T21:23:43.637Z
User123
<p>I have a masters in chemistry but pretty much, a layman in astronomy.</p>
<p>So, can you please explain to a novice like me, about this paragraph taken from the Wikipedia article on <a href="https://en.wikipedia.org/wiki/Makar_Sankranti" rel="nofollow noreferrer">Makar Sankranti</a>:</p>
<blockquote>
<p>There are two different systems to calculate the Makara Sankranti date: <em>nirayana</em> (without adjusting for precession of equinoxes, tropical) and <em>sayana</em> (with adjustment, sidereal). The January 14 date is based on the <em>nirayana</em> system, while the <em>sayana</em> system typically computes to about December 23, per most Siddhanta texts for Hindu calendars.</p>
</blockquote>
<p>Am I correct to understand that when the date was assigned in Hinduism some thousand (?) years back, the winter solistice used to be on 14th/15th January?</p>

<equinox>
Understanding date of astronomical events
AvadaMouse
# Understanding date of astronomical events

(Asked by: username_0 on 2020-12-20)

I have a masters in chemistry but pretty much, a layman in astronomy.

So, can you please explain to a novice like me, about this paragraph taken from the Wikipedia article on [Makar Sankranti](https://en.wikipedia.org/wiki/Makar_Sankranti):

> There are two different systems to calculate the Makara Sankranti date: *nirayana* (without adjusting for precession of equinoxes, tropical) and *sayana* (with adjustment, sidereal). The January 14 date is based on the *nirayana* system, while the *sayana* system typically computes to about December 23, per most Siddhanta texts for Hindu calendars.

Am I correct to understand that when the date was assigned in Hinduism some thousand (?) years back, the winter solistice used to be on 14th/15th January?

**Tags:** equinox


---

## 1 answers

### Answer by username_1 on 2020-12-20. Score: 0 | Accepted answer

Precession of equinoxes means that the North pole of the Earth is changing its direction. This also means, that the dates of the seasons (seen from outside the Solar System (= sidereal)) are changing. *Nirayana* calculates the date of Makar Sankranti with adding years to the first Makar Sankranti, but *sayana* calculates the date of Makar Sankranti relative to stars (sidereal).

In a nutshell: *nirayana* is on the same *date* as the first event (first Makar Sankranti), but *sayana* is on the same *event* as the first Makar Sankranti (winter solstice). Yes, winter solstice was once on the 14 January.


---

