The crossing: tropical zodiac, sidereal zodiac and divisional charts

For six nights you have been reading the tropical zodiac, set on the seasons: its 0° Aries is the point where the Sun stands at the spring equinox. The astrology of India, Jyotish, reads the sidereal zodiac, set on the stars.

Both have twelve signs of 30°, in the same order. Only the starting point differs: the Earth’s axis turns slowly, like the axis of a spinning top, and the equinox slips back against the stars by 1° every 72 years. Today the gap is about 24°: it is called the ayanamsa.

Neither is wrong: the planets are in the same place, only the scale starts at a different notch. The tropical zodiac speaks of the seasons, the rhythm you live by; the sidereal one, of the stars and the long run.

From tropical to sidereal, you subtract 24°. Two cases. The degree is 24 or more: the sign stays the same, 28° Leo becomes 4° Leo. The degree is smaller: you step back one sign and add 6, since 30 minus 24 leaves 6.

The Sun of the example sky is at 21° Taurus in the tropical zodiac: 21 is smaller than 24, so it steps back into Aries, at 21 plus 6, which makes 27° Aries in the sidereal zodiac. It gains a dignity there: Aries is the sign of the Sun’s exaltation.

From sidereal to tropical, the road runs the other way: you add 24°. From 30 upward, you take away 30 and move on one sign: 15° Pisces plus 24 makes 39, which is 9° Aries. That is Venus in the example sky.

Once every position is converted, you get the D1: the Vedic birth chart. It holds nine bodies, the grahas: the Sun, the Moon, Mars, Mercury, Jupiter, Venus, Saturn, and the two nodes of the Moon, Rahu and Ketu. Uranus, Neptune and Pluto have no place in it.

There the Ascendant is called the lagna, and houses are counted differently: one house per sign. The sign of the lagna is the whole of house 1, the next sign is house 2, and so on.

The example sky has its lagna in Leo: Virgo is its house 2, Aries its house 9. Its Sun therefore stays in house 9, as in the tropical chart, but it has changed sign: Taurus on one side, Aries on the other.

Jyotish then looks closer. It cuts each sign into equal parts, and each part sends the planet to a sign: that gives a new chart, the divisional chart. The D9 cuts each sign into nine, the D10 into ten, the D60 into sixty. Each one is a lens laid over the D1, never read without it.

The D9: partnership, dharma, what the soul ripens, where you are going. The D10: career and your place in the world. The D20: spiritual life and practice. The D60: past-life karma, where you come from.

The D2: wealth and resources. The D4: home and property. The D7: children. The D12: parents and lineage. The D24: studies and knowledge.

The D9 is the most important chart after the D1: the chart of maturity. In it, each sign is cut into nine parts, the navamshas: 30° divided by 9, which makes 3°20′ each. One degree holds sixty minutes of arc: 20′ is a third of a degree.

The boundaries are quick to learn: 3°20′, 6°40′, 10°, 13°20′, 16°40′, 20°, 23°20′, 26°40′, 30°. Three parts make exactly 10°: part 4 starts at 10°, part 7 at 20°.

To find the part a planet is in, count the whole parts already passed and add one. At 15°: four parts have passed, the fourth ends at 13°20′, so the planet is in part 5. At 27°: eight parts have passed, so it is part 9.

What remains is the sign of that part. You count from the cardinal sign of the same element as the sign the planet is in: Aries for fire, Capricorn for earth, Libra for air, Cancer for water. Part 1 is that starting sign, part 2 the next one, and so on.

Mars in the example sky is at 22° Aquarius in the sidereal zodiac: part 7 of an air sign. Libra, Scorpio, Sagittarius, Capricorn, Aquarius, Pisces, Aries: it is in Aries in the D9.

A planet in the same sign in the D1 and in the D9 is called vargottama: strengthened, it delivers what it promises. Here the lagna (15° Leo, part 5 from Aries) and Saturn (1° Capricorn, part 1) both are.

Two divisions work for every chart. The first gives the size of one part: 30° divided by the number of parts. In the D2, 15°; in the D3, 10°; in the D9, 3°20′; in the D10, 3°; in the D12, 2°30′; in the D20, 1°30′; in the D60, 0°30′, half a degree.

The second tells the accuracy you need. The birth Ascendant changes sign about every two hours, that is 120 minutes; the Ascendant of a chart Dn changes every 120 divided by n minutes. In the D9, about 13 minutes; in the D10, 12; in the D12, 10; in the D20, 6; in the D24, 5; in the D60, 2.

The finer the chart, the more exact the birth time must be. A time rounded to the quarter hour can already shift the lagna of the D9; the D60 asks for the time written on the birth certificate, to the minute.

You now hold several charts of the same sky. Crossing follows an order: the tropical chart, then the D1, then the chart of the area (the D9 for partnership, the D10 for career), and finally time. Transits and the solar return say when what the charts promise comes alive.

What comes back is solid: Saturn in the example sky is in Capricorn in the tropical chart, in the D1 and in the D9, a trait confirmed three times. What diverges is a nuance, never an error: Venus is in detriment in Aries in the tropical zodiac, exalted in Pisces in the sidereal one. Two lights to hold together.

One thing is left: the great sky, fifteen questions that cross the whole path. At the end of the line drawn by Merak and Dubhe, Polaris is waiting for you.