How to cast a horoscope

I want you to understand how to check and calculate Ascendant (Lagna) and the latitudes of the 9 planets so that you know how it is done.

The calculations given in the Example here are from the published Ephemeris pages are from The Lahiri Ephemeris. They are the most reliable ones published in India and majority of the Vedic astrologers follow them. They are based on the London Nautical Almanac and are quite accurate. However the modern software using the NASA ephemeris are a lot more accurate.

Worked out Birth Chart example

A person is born in Calcutta, at 15hr18min30sec, IST on 12-6-1948.

Calculate the Lagna, the planetary positions and give birth chart along with, Birth Star, Tithi & Yoga

1^st calculate the Lagna or ascendant

The birth time given in Indian Standard Time must be 1^st converted in to Local Mean Time of Calcutta and then a correction to be applied to the Sidereal Time.

The Local Mean Time difference for Calcutta from Indian Standard Time is:

(+)23min:30sec and the correction to be applied to the Sidereal Time is (-)0min:04sec

a)The Indian Standard Time is                                                                                          15h 18m 30s

b)The correction for Local Mean Time                                                                                            (+)23m 30s

                                                                     ——————

Hence the Local Mean Time is                                                                                    15h 42m 00sec

Now find the sidereal time for this date at Calcutta from the Sidereal Time Table A. Please note that the sidereal time is always given for 12:00 noon

c)Sid. Time for June 12     (from Sidereal Time Table for 12 noon)                                     5hr 20min 31sec

d)Correction for year,1948 (Sidereal Time Table entry for 1948 with cross)                     (+)1min 28sec

e)Correction for Calcutta   (as given at the start re Calcutta correction)                                     (-)0min 04sec

                                     ———————-

Hence the Sidereal time for June 12, 1948 (noon) is                                                          5hr 21min 55sec

The birth time LMT is 15h 42m 00s. Hence it is 3h 42m 00 after the Sidereal noon time. So we have to add this difference in time of 3h 42m 00 and also a correction to the sidereal time for the increase in time. Table 4 gives the corrections to time. The correction given is 30 seconds for 3 hours and 40 seconds for 4 hours. Hence by calculating we get 36 seconds correction for 3hr 18min 30sec.

f)Sidereal time for June 12, 1948 (noon) is                                                                           5hr 21min 55sec

g)Add difference in time from noon                                                                                  (+) 3hr 42min 00sec

h)Correction to increase in time from Table IV                                                                                     (+)36sec

                                                                                                                                         —————————

i)Adding we get the Sidereal time                                                                                        = 9hr 04min 31sec

j)Now check the Table of Ascendants for Calcutta. Against 9h 04m. we get the ascendant>     6s 18° 52′

The next value for 9h 08min is 6s 19° 45′. So if the difference for 4 minits is 53′,

k)by calculating we get 6′ 51” for 31 sec.

l)So by adding                                                                                                                                   00° 06′ 51”

m)we get for 9h 04m 31sec                                                                                                         6s 18° 58′ 51”

For Sidereal Time 9h 04m, from Ascendant Table Calcutta the Ascendant is                           6s 18° 58′ 51”

n)Now check the Ayanamsa Correction Table for 1948. The correction is                                        (-) 0 08

Hence the total is 6s 18° 50′ 51”

Please note: In most of the Ephemeris the planetary longitudes are given as follows:

Starting from Aries, the number of houses crossed is marked by “#s” and the degrees as “ ° ” minutes as “ ‘ ” seconds as “ ” ”. Hence:

If it is in 28° 30′ it will be given as 0s 28° 30′ – in Aries

If it is in 63° 10′ it will be given as 2s 03° 10′ – in Gemini

If it is in 224° 40′ it will be given as 7s 14° 40′ – in Scorpio

Hence the Ascendant in this case is Tula or Libra 6s 18° 50′ 51”. This is quite accurate as the computerized calculation gives the Lagna Libra 18° 50′ 55”. The other Planetary longitudes for Calcutta, at 15hr18min30sec, IST on 12-6-1948 at are as follows:

The Lagna or Ascendant as per our calculations has crossed 6 houses and is in Libra 18° 50′ The other planets as we can see > Sun has crossed one house and is in Taurus, Moon has crossed 4 houses and is in Leo, Mars has crossed 4 houses and is in Leo, Mercury has crossed 2 houses and is in Gemini, Jupiter has crossed 8 houses and is in Sagittarius, Venus has crossed 2 houses and is in Gemini, Saturn has crossed 3 houses and is in Cancer, Rahu has not crossed any houses and hence in Aries and Ketu has crossed 6 houses and is in Libra.

Janma Nakshatra or Birth Star calculation: The star constellation in which moon is placed at the time of birth is called Janma Nakshatra. It is calculated as follows:

Moon’s Longitude is 123:51

Makha starts at 120 degrees. Makha 1^st quarter is up to 123:20 as each quarter is of 3:20

Hence we can see that Moon has crossed the 1^st quarter of Makha and is in the 2^nd quarter.

Hence the persons Janma Nakshatra or Birth Star is Makha 2^nd Pada.

Tithi calculation:   

The Sun’s Longitude is                             58:10

the Moon’s Longitude is                          123:51

Deducting we have                                   65:41

Dividing by 12 we have 5 and balance 5:41. So 5 Tithis or Lunar phases are over and it is the 6^th Tithi called Sasthi.

As moon is ahead of Sun it is Shukla Paksha or Bright Half or Waxing Phase.

(Had it been behind Sun it would have been Krishna Paksha or Dark Half or Waning Phase).

So the person is born on Shukla Paksha Sasthi Tithi.