In Indian Astrology, each day of the week has been assigned its respective
ruling planet viz. Monday is ruled by Moon, Tuesday by Mars etc. However,
Rahu and Ketu have not been given any specific day as they are treated as
nodes. However, Rahu and Ketu are given one and half hours time in a day
resulting three hours for Rahu and Ketu in which they can cast their malefic
influence since Rahu is a natural malefic.
Rahu Kalam (Rahu Kaal) is an inauspicious period of time for a particular day.
In other words, Rahu Kalam is the time during which Rahu seizes the
opportunity for influence. During this time one should avoid any auspicious
work like starting new business or project, buying expensive items,
investments, business transactions, journeys, meetings, interviews etc. It is
believed that any thing lost during Rahu Kalam is never found.
Rahu Kaal is one-eighth part of the difference between the Sunset and
Sunrise time of a particular place for a specific day of the week. The reason
for its 8th part is that in some Indian astrology systems, Rahu is considered
to be the 8th planet.
To calculate Rahu kalam or Rahu kaal, first find the local Sun-rise time and
sun-set time of the place. This can be found from a local panchang or your
local newspaper. Next divide the difference between the two time periods
into 8 equal parts. There is no Rahu Kalam during the first period of any
weekday. In other words, it is never just after sunrise. From Monday to
Sunday the period of Rahu Kaal or Rahu kalam for each week day is then
calculated as described below:
On Monday Rahukalam falls on the 2nd period
Saturday 3rd period
Friday 4th period
Wednesday 5th period
Thursday 6th period
Tuesday 7th period
Sunday 8th period