This method of casting the horoscope of a native using prashna is called “ NASHTA JATAKA”. The year, ayana, ritu, month, paksha, thithi, nakshatra, ascendant, Moon etc. may be found out from the prashna chart. First we have to cast the prashna chart, along with other varga charts, for the person who wishes to know the details of his birth.
1. YEAR OF BIRTH: Cast Dwadasamsha chart of the prashna chart. The sign occupied by Moon in D12 will indicate the position of JUPITER in the Birth chart. From this the year in which Jupiter transited can be found out. As Jupiter transits one sign for roughly one year, we get the year of birth in the broad span of 12 years, closest to the rough age of the native.
2. AYANA: If the prashna lagna is in the FIRST HORA, then it is UTTARAYANA and if in the SECOND HORA, and then it is DAKSHINAYANA.
3. SEASON: Different planets represent the following seasons.
The lord of the Drekhana of Prashna lagna gives us the season in which the native was born. It may so happen that there is contradiction between the ayana and the season.
In that case take Mercury in place of Mars, Venus in place of Moon and Saturn in place of Jupiter and vice versa. Out of seven planets as drekhana lords, Sun is not to be replaced for any other planet.
4. MONTH: After the season is fixed, the month is to be fixed. The six seasons are related to the Sun’s transit in different nirayana signs. Now again see the lagna of the prashna chart. We have already seen in which drekhana the prashna lagna falls. The first part of the drekhana represents the first month of the season and the second part of drekhana represents the second month of the season.
5. DATE OF BIRTH: See the drekhana of the prashna lagna. The entire drekhana represents 30 days resulting in 3 days for one degree of drekhana or 1 day for 20 minutes. The elapsed degrees of drekhana indicates the elapsed dates. Thus the date and Sun’s degree can be assessed.
For example, the longitude of prashna lagna is 16 degrees and 20 minutes, in the second drekhana in which 6 degrees and 20 minutes have elapsed. Now taking 1 degree for 3 days and 20 minutes for one day, we get the number of days elapsed from the SUN’S ENTRY in the sign as (3x6)+1 = 19 days. We know the date when Sun entered into that particular sign. Add 19 days to the date of Sun’s entry to get the date of birth.