A mathematical way to calculate the Rahu period

My friend A and I were recently talking about Rahu Kalam (period) and how hard it is to remember the exact time for each particular day (Monday-Sunday). So we came up with an easy equation that would help you calculate the Rahu period on any particular day.

But, before we get into that, we need to know, what exactly is Rahu?

Rahu is one part of the Navagraha - that is worshipped across India. The Navagraha is a set of 9 (Nava) heavenly bodies that are believed to influence the life of a human being.

These 9 heavenly bodies include — Surya/Suryan (the Sun), Chandra/Chandran (the Moon), Mangal/Chevvai (Mars), Budhan (Mercury), Brihaspati/Guru (Jupiter), Shukra/Shukran (Venus), Shani (Saturn), Rahu (Northern node of the moon), and Ketu (Southern node of the moon).

Why exactly is Rahu Kalam considered to be an inauspicious time?

The whole Vedic astrology concept is a complex topic to dwell on, and I don’t want to speak on something I fully don’t understand. I just know that Rahu Kalam is considered inauspicious and is diligently followed by many people, especially in the Southern part of India.

It is calculated by dividing the duration of the daytime, 12 hours in India, by 8. It could differ according to the place you live in.

720 mins/8 = 90 mins a day. This 90 minute period is distributed to every day of the week, starting from Monday.

Here’s how the timing differs for each day:

Monday: 7:30 am — 9:00 am
Tuesday: 3:00 pm — 4:30 pm
Wednesday: 12:00 pm — 1:30 pm
Thursday: 1:30 pm — 3:00 pm
Friday: 10:30 am — 12:00 pm
Saturday: 9:00 am — 10:30 am
Sunday: 4:30 pm — 6:30 pm

If you take a look at this closely, the timings are not consecutive with the flow of the days. And hence, remembering the time, for most people, would be hard. So people have come up with an easy way to remember this —

Mother Saw Father Wearing The Turban Slowly

Mother = Monday — 1
Saw = Saturday — 2
Father = Friday — 3
Wearing = Wednesday — 4
The = Thursday — 5
Turban = Tuesday — 6
Slowly = Sunday — 7

This ordering of the days will result in the flow of the Rahu period itself. But remembering the order of these days, and associating it with a particular time itself is time-consuming.

This is where the equation my friend and I came up with, comes into play.

(n-1)*1.5 , where, 2 ≤ n ≤ 7

Given that, at “n=1", Rahu period is from 7:30 am — 9:00 am.

Add the answer you get (in hours) to 7:30 am, and you shall have your Rahu starting period for the day.

For example, say you want to know the Rahu period for Thursday.

Thursday = The = 5. Using the equation, (5–1)*1.5, we get 6 hours.

Now, by adding 6 hours to 7:30 am, you get 1:30 pm. This means that the Rahu period for the day is from 1:30 pm to 3:00 pm.

A simple and quick way to calculate the period, without having to remember a lot. I would say “simple" for people who like doing math.