I have written a post for beginners about the math in Jyotish. There was a question so continuing on the math.

I have recommended equal house system with shifting of houses for beginners in my earlier post. This system is adequate for learning the basic concepts and especially in India where the northernmost latitude is 37deg North, it does give reasonably reliable results but you may not be able to precisely time events.

The system recommended by our standard books is the unequal house system. Especially if the birth is beyond the tropics or if the ascendant lies at the very start or the very end of the sign, the unequal system has to be applied. Advanced students should learn to use this in their practice. Doing these calculations by hand requires an understanding of the math involved and it does take time.

I am using the sample chart, Aleister Crowley, 12^th Oct 1875, 11: 42pm, Leamington Spa, Britain. I prefer using dead people’s charts for analysis. If you use a living person’s chart as an example chart, the act of dissecting the horoscope does interfere with his life.

First, this birth chart below is calculated using equal houses/bhav, ie every house is considered to have the exact width of 30deg. I have used this chart in several posts in my blog. You do not have to do any math by hand, just input the details into the app and everything including the divisional charts is available instantly.

I have not yet come across a full fledged app for the unequal houses system. (If you know of any then do use that one. But check if it follows the calculations given in the BPHS.) This table below is the calculated data for the unequal house system. Here the first column ‘Bhav’ is the house, eg 1st bhava is the 1st house/ the ascendant. Then ‘Madhya’ is the degree at the center of each of the houses. And ‘Sandhi’ is the degree at which each of the houses end. Both these degrees are in the degree- minute format.

As you can see here the houses are of different widths, they are unequal in size. We already have the positions of the planets, so we will arrange the planets in these twelve unequal houses. And this is what we get,

• The 1st house is from 27deg 16min Gemini to 27deg 16min Cancer. It is 30deg in width and it contains the Ascendant degree/Lagna.
• The 2nd house is ruled by Leo and is from 27deg 16sec Cancer to 20deg 4min Leo, it is 22deg 48min wide.
• The 3rd house is ruled by Virgo and is from 20deg 4min Leo to 12deg 53min Virgo.
• The 4th house is ruled by Virgo again and is from 12deg 53min Virgo to 12deg 53min Libra. It contains Ketu, Sun and Venus.
• The 5th house is ruled by Scorpio and is from 12deg 53min Libra to 20deg 4min Scorpio, it is 32deg 57min wide. It contains Jupiter and Mercury.
• The 6th house is ruled by Sagittarius and is from 20deg 4min Scorpio to 27deg 16min Sagittarius.
• The 7th house is ruled by Capricorn and is from 27deg 16min Sagittarius to 27deg 16min Capricorn. It contains Mars.
• The 8th house is ruled by Aquarius and is from 27deg 16min Capricorn to 20deg 4min Aquarius. It contains Saturn.
• The 9th house is ruled by Pisces is it extends from 20deg 4min Aquarius to 12deg 53min Pisces. It contains the Moon.
• The 10th house is ruled by Pisces and it extends from 12deg 53min Pisces to 12deg 53min Aries. It contains Rahu.
• The 11th house is ruled by Taurus and it is from 12deg 53min Aries to 20deg 4min Taurus.
• Finally the 12th house is ruled by Gemini and it is from 20deg 4min Taurus to 27deg 16min Gemini.

This unequal house chart as you can see, is different from the equal house chart which we were using in our beginner level posts. And there are several points for interpretation, eg,

• Houses which are larger in size have more influence on the person’s life than the houses which are comparatively smaller in size.
• Generally two signs or even three signs can contribute to a house. Thus interpreting the chart requires skill and practice.
• The sign which falls in the bhav madhya rules that house. eg Cancer rules the 1st house and its owner Moon is the ruler of the 1st house/Lagnesh. Similarly Leo rules the 2nd house, and the Sun is the Bhavesh of the 2nd bhav/house.
• One sign can sometimes rule over two houses. In this chart, Virgo rules the 3rd and 4th houses. And Pisces rules the 9th and 10th houses. So Mercury and Jupiter rule 3 houses each in this chart and this requires detailed analysis.
• The signs, Libra and Aries do not own any of the houses. This means that these signs become the most malefic for this chart. Mars and Venus too must be evaluated critically as now they own only 1 house each in the chart.

Next step. The unequal house chart is the D1, the first divisional chart. You will now have to calculate the further divisional charts by hand (of if you can find an app which does all this). And this requires an understanding of the math involved. For accurate predictions you need to use at least the D9, Navamsha chart. (With the equal house system you just had to input the details into your app and you would get the D9 and other divisional charts immediately.)

eg for calculating the Navamsha,

• every house/bhava is divided into 9 equal divisions which are the amsha. There are in total 108 amshas for the 12 houses.
• The amsha are then allotted to the 12 signs of the zodiac in a fixed sequence and every sign of the zodiac rules 9 amshas each.
• Finally the the planets are allocated to the correct amsha as per their degrees.
• In the equal house system doing this was easy, 30deg/9 = 3deg 20min uniformly for every amsha.
• But now in the unequal system each house has a different width. In our example above the 1st house has a width of 30deg so its 9 amshas will have a width of 3deg 20min. But for the 2nd house, its width is 22deg 48min. So the 9 amshas of the 2nd house will have a width of (22deg 48min)/9 = 2deg 33min each. Similarly you will calculate the width of the amshas of the remaining houses. Then allocate these 108 amshas of varying widths to the correct signs. And then finally allocate the ascendant degree and planets to the amshas. Thus you would get the navamsha D9 divisional chart.

This, very briefly, is the unequal house system. (Wrote another post on this here.) This is given in some translations of the BPHS. But the english translation has omitted the entire chapter of Bhavchalit.

For learning Jyotish three things are necessary,

1. Math – Jyotish is Math. Today most astrologers are zero in the math, everyone wants to start making predictions without understanding the mathematical concepts.
2. Sanskrit. All our texts are in Sanskrit. Reading Sanskrit is a good way to begin. But for understanding what the Jyotish sutras mean, you have to study under a genuine Jyotishi. Jyotish is a Vidya, you need a Guru.
3. Mantra siddhi. Jyotish is a Vedang. It means that unless you have an auspicious Dharma trikon, you cannot make accurate predictions.

To summarise,

• If you want to make accurate predictions for births beyond the tropics and especially for charts where the ascendant degree is almost at the start or end of a sign you have to use unequal house system as recommended by BPHS.
• If your place of birth is beyond the tropics then do ensure that your regular astrologer uses the unequal house system, because the equal house system will give you only approximate predictions. (Several practicing astrologers do not even read the BPHS. They just copy from their softwares and cheat their clients.)

But for beginners, use the equal houses (post here) until a time when you feel more confident with doing the math by hand and only then start with the unequal houses.