In a horoscope there are 12 houses and there are 12 signs. But there are different ways of fitting the houses over the signs, different math and different systems of astrology. The main system in Vedic Jyotish is the Parashari system by Rishi Parashar. The entire text of the Bruhat Parashar Hora Shastra is available, it is detailed, mathematical and gives answers. It is the fundamental system of Jyotish. Others have modified Parashari as per their own concepts creating systems like Jaimini and KP.
For beginners it is best to learn Parashari first.
Now to draw the horoscope. Ideally the Shripati system is used to calculate the houses. It is an unequal house system. Currently no one uses it much as there is no reliable software for this and calculating by hand for every chart is tedious. Here the ascendant degree will be at the exact center of the 1st house. And simultaneously the descendant degree at the exact center of the 7th house. The zenith will be the exact center of the 10th house and the nadir at the exact center of the 4th house. Houses as per Shripati can be exactly 30deg or lesser or more than 30deg in extent. All the house/ bhava in a horoscope will be exactly 30deg in width only if the birth was on a day when the day and night duration was exactly 12hrs at that time/ place. In all other cases, the houses will always be greater or lesser than 30deg in width and you will have varying widths for various houses in a single chart, unequal houses. So doing its calculations requires a good understanding of math. (If you are good at math then read ‘Sripati paddhati’ by V.S.Shastri. )
But to make all this simpler for students,
- If the birth location is within the tropics of Cancer and Capricorn, use the Equal houses system with Bhav-chalit. Here each of the 12 houses will be 30deg in width. It is simple to understand and will give sufficiently accurate results.
- If the birth place is beyond the tropics then professional Vedic astrologers will apply the Shripati system in toto. But for students, use the same Equal house system with Bhav-chalit as an approximation. This will still give reasonably accurate answers.
So we will always use Equal house system with Bhav-chalit in Parashari.
- Here each house will be 30 deg in width. Equal houses.
- The ascendant degree will be at the exact center of the 1st house. Here is where we will use Bhav-chalit.
How to do the Bhav-chalit shifting.
1. If your birth rising degree is exactly 15 deg then you do not have to do any shifting. Use the horoscope provided by the software. The rising degree is already at the center of the 1st house. The house and the sign will exactly overlap. ie if your rising degree is 15deg Scorpio, then the 1st house will be exactly the same as the sign Scorpio. The second house will be exactly the same as the Sagittarius sign and so on.
2. If your rising degree is between 0 to 14 deg then you have to do a correction for shifting the planets. Suppose the rising is at 5deg Scorpio. So add and subtract 15deg to this to get your 1st house. The rising degree has to be at the center of the 1st house.
- The 1st house will be from 20deg Libra to 20deg Scorpio. The rising degree Scorpio 5deg is the exact mid-point of the 1st house. The sign and the house do not overlap as the house is partly in Libra and partly in Scorpio signs. In this if eg Saturn is in 25deg Libra then this Saturn will be in the sign Libra but shift to the 1st house. So Saturn’s results have to be interpreted as per Libra sign in the 1st house
- The second house will be from 20deg Scorpio to 20deg Sagittarius. If Mercury is in 29deg Scorpio then he will be considered to have shifted into the 2nd house of the horoscope. His result will be as per Mercury in Scorpio sign in 2nd house
- Ie any planet beyond 20deg in a sign will shift into the next following house.
3. If the rising degree is between 16-30 deg you have to apply the shift here too. Suppose the rising degree is at 25deg Gemini. Add and subtract 15deg to get the degree extent of the 1st house.
- So here the 1st house will extend from 10deg Gemini to 10deg Cancer. The rising 25deg Gemini will be the exact center of the 1st house. If you have eg Jupiter at 4deg Cancer then he will be considered to be in the 1st house. Jupiter’s results will be as per Cancer sign in 1st house.
- The 2nd house will be from 10deg Cancer to 10deg Leo. And eg if you have Venus in 6deg Gemini then this Venus shift to the 12th house for this chart, but his sign remains Gemini. Venus’s results will be as per Gemini sign in 12th house.
- Ie any planet who is placed till 10deg of any sign will shift backwards into the earlier house.
In Equal house with bhav-chalit,
- the extent of each house is 30deg.
- The ascendant degree is at the centre of the 1st house.
- The planets can shift their houses but will never change their signs.
This was how to shift the planets with the Bhav-chalit concept.
You have to remember one more thing. In the case (2) and (3) above, where the rising degree is not at the very center of the sign, each house in the horoscope contains two signs. So interpreting the chart requires some practice. Especially if the rising degree is at the very edge of the sign.
If the birth rising sign is at the very edge, eg it is at 1deg Libra. Then the 1st house will be from 16deg Virgo to 16deg Libra. ie it will be composed of the 16-30deg Virgo section and 0-16deg Libra section. The 1st house is practically 45% Virgo and 55% Libra. Similarly for the rest of the houses, each house will carry influences of both the signs which compose it. Here in this example this persons facial features will be a mix of Virgo and Libra. The way he talks, his family life will be a mix of Libra and Scorpio, this is the 2nd house and so on. So be careful while interpreting such charts.
In fact with such charts your software will not give accurate readings if it does not take the bhav-chalit into account. You may also be required to do some calculations by hand. eg when planets shift houses you have to calculate the Ashtakvarga by hand in case your software does not consider the shifted positions of the planets.
With the advent of software, astrology students have stopped learning the math. I would advise you to at least draw your own horoscope, the 10 divisional charts and the Ashtakvarga table by hand. This exercise will be very helpful in understanding the basic concepts. Jyotish is math+intuition fuelled by your spiritual practice.
There are two variations to the original Parashari system which are popularly used by astrologers.
1.Jaimini system is an important system but it is a bit cryptic. There are texts missing or partially understood. You can learn it if you wish to. The house/ bhavas are calculated the same as original Parashari. Ie you will use Equal house system with Bhav-chalit.
2. Krishnamurthi paddhati/ KP system is a system developed in the past century. He uses the Placidus system for setting up the horoscope. Here the concept is that the first house starts with the rising degree. Ie if your ascendant degree is 20deg Aries then your first house will begin with 20deg Aries and will extend till 20deg Taurus. If you are following KP system, you have to compulsorily use Placidus as KP does not use the bhava/ house concept but uses a novel star lord and sub-lord etc concept. KP is an accurate system but is different from the original Parashari.
You cannot use Placidus with Parashari or Jaimini, if you do, the readings will be inaccurate.
For students and the casual enthusiasts this debate on which maths or system to use can be confusing. I had got a question on this so this post is the simplest practical answer. (I have not discussed 3D geometry or astronomy as it would create more confusion).
So to begin with, learn Parashari with the Equal house system and Bhav-chalit. Later when you get more confident of the math/ concepts you can learn Jaimini or KP or try out your own theories on your study samples.