2. CONFIDENTIAL & RESTRICTED
Names of Days of Week
Days of the week
Sunday Monday Tuesday Wednesday Thursday Friday Saturday
(Ravivara) (Somavara) (Kujavara) (Budhavara) (Guruvara) (Shukravara) (Shanivara)
Duration of Day : 24 hours (Each hour called as a Hora)
Duration of day = Dinamaan
Duration of night = Ratrimaan
The name of the first Hora (Hour) of the day starting from Sunrise is
that of the lord of the day
3. CONFIDENTIAL & RESTRICTED
Names of Days of Week
The lords of the subsequent Horas go by the following order:
Arka Shukra Budha Chandra Manda Jeeva Dharasutha
(Sun) (Venus) (Mercury) (Moon) (Saturn) (Jupiter) (Mars)
Sun
Venus
Mercury
Moon Saturn
Jupiter
Mars
On a Sunday, first Hora belongs to Sun.
2nd Hora belong to Venus, 3rd Hora to Mercury……
The cycle repeats to complete 24 horas in a day
25th hora lord will the lord of the next day
4. CONFIDENTIAL & RESTRICTED
Question (1)
• Which is the 8th Hora of Tuesday ?
1st Hora of Tuesday belongs to Mars
2nd Hora belong to Sun
3rd Hora belongs to Venus
4th Hora belong to Mercury
5th Hora belongs to Moon
6th Hora belongs to Saturn
7th Hora belongs to Jupiter
8th Hora belongs to Mars
Arka Shukra Budha Chandra Manda Jeeva Dharasutha
• There are 7 planets ruling the
Horas.
• 1 cycle completes in 7 hours
• 8th Hora starts from the second
cycle. Hence on Tuesday 8th
Hora belongs to Mars
5. CONFIDENTIAL & RESTRICTED
Question (2)
• Which is the 16th Hora on Friday
Remove multiples of 7. (Hence removing 14).
15th Hora starts with first Hora of day = Venus
16th Hora belongs to Mercury
6. CONFIDENTIAL & RESTRICTED
Practical Calculation
• All previous calculations assumed exactly 24 hours a day and 1 Hora
to be 1 Hour. In practical purposes its not the case.
• Calculate Dinamaan = Sunset – Sunrise
Dinmaan / 12 = Duration of 1 Hora
during day
• Calculate Ratrimaan = Sunset-Next Sunrise
Ratrimaan / 12 = Duration of 1 Hora during night
Sunrise Sunset
Sunset
Next Sunrise
7. CONFIDENTIAL & RESTRICTED
Question (3): Find out the Hora lord at 7.28
AM on 07-Dec-2021
• Day : Tuesday (Hora Lord Starts with Mars)
• Sunrise on 07-Dec-2021 = 6.29 AM
• Sunset on 07-Dec-2021 = 5.52 PM (17.52)
• Since the hora has to be found out during daytime, calculate Dinmaan =
Sunset – Sunrise = 11h 23m
• Duration of 1 Hora = Dinamaan/12 = ((11*60)+23)/12 = 56.91
= 56m 55sec = ~ 57 minutes
• First Hora : 6.29 AM – 7.26 AM (Mars)
• Second Hora : 7.26 AM – 8.23 AM (Sun)
• Hence the Hora at 7.28 AM belongs to Sun (second hora of day)
12. CONFIDENTIAL & RESTRICTED
Meridians of India
• Time is measured based on the
Longitude towards East or West
from the Greenwich Meridian
Longitude (0 degrees)
• The time at Greenwich is knows as
Greenwich Meridian time (GMT)
• Indian Standard Time is measured
at Standard Meridian of 82.5
degrees East from Greenwich
Meridian Longitude
13. CONFIDENTIAL & RESTRICTED
Earths Rotation
• Earth rotating from west to east, eastern part of earth will see Sun
first and slowly the western parts.
• Eg: Sunrise in Kolkata is before sunrise in Bangalore
• Earth completes one rotation in 24 hours ; It completes 360° of
movement.
• 24 hours = 24 * 60 min = 1440 minutes
• For 360°, time is 1440 minutes
• Hence for 1° = 4 minutes
Note : There are 2 units used above:
Time Measurement : In hours, minutes & seconds (h, m , s )
Arc Measurements : In degrees, minutes & seconds (° , ‘ , “ ) . Eg: 10° 33' 19“
1 hour = 60 minutes; 1 minute = 60 seconds
1 ° = 60’ ; 1 ‘ = 60 “
14. CONFIDENTIAL & RESTRICTED
Zonal Standard Time & Timezone
• Hence the concept of Local Mean time arises as the time at individual
places differ.
• Those places towards east are always ahead of time relative to the places
to their west.
• In few countries, (eg. Unites States), the whole country is divided into few
zones (4 zones for US) and for each zone standard meridians are defined.
• Timezone – For simplicity , a standard meridian is defined for a zone or a
country . For example : Indian Standard Time
• Timezone towards east to Greenwich is denoted by (+)
• Timezone towards West to Greenwich is denoted by (-)
15. CONFIDENTIAL & RESTRICTED
Question (4): Find out the time zone of India
• The standard meridian for India = 82° 30’ East of Prime Meridian
• We know 1°= 4 minutes
(60’ = 240 seconds) ; 1’ = 4 sec
• Hence for 82° 30’ = 82 * 4 min : 30’ * 4 sec
= 328 min : 120 sec = 330 mins
= 5 hours 30 minutes
Hence Timezone of India is GMT + 5.5 (5h 30min)
16. CONFIDENTIAL & RESTRICTED
Question (5): Find out the longitude of standard
meridian of for Mexico if it falls in timezone (-6
hours)
• Timezone is (-) means its longitude is towards west to Greenwich
• Timezone = 6 hours = 6 * 60 mins = 360 mins
• As 4 mins = 1 ° , 360 mins = 360/4 = 90 °
• Hence the standard meridian of Mexico is = 90° W
17. CONFIDENTIAL & RESTRICTED
Question (6): If time of birth of native born at
Delhi is 10:30 AM (IST), then find out LMT of birth
of native
• Longitude of Standard Meridian of India = 82° 30’ E
• Longitude of Delhi = 77 ° 13’ E
• Difference of the 2 longitudes = 82° 30’ - 77 ° 13’
= 5 ° 17’
• Multiplying by 4, we get = (5 * 4) mins + (17 * 4) sec
= 20 mins + 68 sec = 21m 8s
• Since Delhi is to West of standard meridian of India, we need to (-)
• Hence LMT = 10:30 – 21m 8s = 10h 8m 52s
18. CONFIDENTIAL & RESTRICTED
Homework : If a native is born Bangalore at 1.30
PM (IST), find out the LMT at birth (Longitude of
Bangalore : 77° 36’)
