D20 Chart Calculator - Vimsamsa Chart
A free vimsamsa (D20) chart calculator — twenty parts of 1 degree 30 minutes per sign, started from Aries, Sagittarius or Leo according to the sign's quality.
The vimsamsa is the D20. Each sign's thirty degrees are split into twenty parts of 1 degree 30 minutes. This calculator, by default, starts the twenty parts of a movable sign from Aries, of a fixed sign from Sagittarius and of a dual sign from Leo, and advances a sign with each part. Twenty parts go once round the twelve signs and eight signs further, so parts 13 to 20 of any sign fall again in the signs of its parts 1 to 8.
The three starting signs are the fire signs, one of each quality: Aries is movable, Leo fixed, Sagittarius dual. The D16 seeds from the same three signs but hands Leo to the fixed signs and Sagittarius to the dual ones; the D20 swaps that pair. Brihat Parashara Hora Shastra states the D20 rule in this form and gives every part a presiding deity, one list opening with Kali for odd signs and another opening with Daya for even signs.
Classically the D20 is consulted for worship, upasana: BPHS assigns worship to the vimsamsa when it lists the uses of its sixteen divisions, while the textbook of P.V.R. Narasimha Rao gives it religious activities and spiritual matters and puts it in what he calls the mental plane, beside the D16 and the D24. The sixteen-chart Shodasavarga weights the D20 at half of a Vimsopaka point; the six-, seven- and ten-chart groupings do not include it.
The twenty parts of Scorpio
Scorpio is a fixed sign, so its count opens at Sagittarius. In the made-up chart used here — Chennai, noon IST, 1 January 1990, invented for these pages and not a real birth — Mars stands 16 deg 07' into Scorpio.
| Part | Arc within Scorpio | Vimsamsa sign |
|---|---|---|
| 1 | 0 deg 00' - 1 deg 30' | Sagittarius |
| 2 | 1 deg 30' - 3 deg 00' | Capricorn |
| 3 | 3 deg 00' - 4 deg 30' | Aquarius |
| 4 | 4 deg 30' - 6 deg 00' | Pisces |
| 5 | 6 deg 00' - 7 deg 30' | Aries |
| 6 | 7 deg 30' - 9 deg 00' | Taurus |
| 7 | 9 deg 00' - 10 deg 30' | Gemini |
| 8 | 10 deg 30' - 12 deg 00' | Cancer |
| 9 | 12 deg 00' - 13 deg 30' | Leo |
| 10 | 13 deg 30' - 15 deg 00' | Virgo |
| 11 | 15 deg 00' - 16 deg 30' | Libra |
| 12 | 16 deg 30' - 18 deg 00' | Scorpio |
| 13 | 18 deg 00' - 19 deg 30' | Sagittarius |
| 14 | 19 deg 30' - 21 deg 00' | Capricorn |
| 15 | 21 deg 00' - 22 deg 30' | Aquarius |
| 16 | 22 deg 30' - 24 deg 00' | Pisces |
| 17 | 24 deg 00' - 25 deg 30' | Aries |
| 18 | 25 deg 30' - 27 deg 00' | Taurus |
| 19 | 27 deg 00' - 28 deg 30' | Gemini |
| 20 | 28 deg 30' - 30 deg 00' | Cancer |
That position lies in part eleven, 15 deg 00' to 16 deg 30', ten signs on from Sagittarius: Libra, the D20 sign the engine returns for that Mars. Sagittarius through Cancer each take two of Scorpio's parts, while Leo, Virgo, Libra and Scorpio take one apiece.
How to read the result
Select D-20_vimsamsa in a cell's menu; in D-number order it follows D-16_shodasamsa and precedes D-24_chaturvimsamsa. The cell then draws the D20 with its own As mark, the vimsamsa of the ascendant degree. Each part is just a degree and a half wide, so this As is far more sensitive to the entered birth time than the rasi chart's lagna is.
The hover text pairs every body's D20 sign with a degree equal to twenty times the rasi-sign degree, less any complete thirties. In every chart Rahu and Ketu stand six signs apart at the same degree, and a sign and its opposite share a quality — Aries and Libra are both movable, Taurus and Scorpio both fixed — so the nodes start from one seed, take one part number and land in one D20 sign. In the sample both are in Leo.
For reading the chart, Narasimha Rao's textbook names the D20 as the division for studying a person's religious activities and works through the D20 of a religious leader by its lagna lord and its 5th and 9th lords. It also links devotion to the D20's 5th house, and the A5 there to the mantras, poojas and rituals through which others see that devotion; the amber A5 in a D20 cell is computed from the D20's own positions.
Key terms
- D-20_vimsamsa
- This chart's key in the cell menus, taken from the engine; it opens the quality-seeded D20 that this page describes.
- Upasana
- Worship or devotional practice, the matter BPHS sets against the vimsamsa in its list of what the sixteen divisions show.
- Movable, fixed and dual
- The three qualities that choose the D20's starting sign: Aries, Cancer, Libra and Capricorn are movable; Taurus, Leo, Scorpio and Aquarius fixed; the other four dual.
- Mental plane
- Narasimha Rao's name for divisions numbered 13 to 24, covering the D16 together with D20 and D24: religiousness, learning, pleasure and other matters of the mind.
- Vimsamsa deity
- A presiding deity BPHS gives to each of the twenty parts, with one list for odd signs and another for even ones; the calculator draws the signs, not the deities.
- A5 of the D20
- The arudha of the D20's 5th house, an amber tag in the cell; Narasimha Rao links it to the rituals and mantras by which devotion is seen.
Three fire-sign seeds
Movable signs start at Aries, fixed at Sagittarius, dual at Leo, so a body's D20 start depends on its sign's quality alone.
Parts of 1 deg 30'
Twenty boundaries in every sign, one each degree and a half — all of them listed above for Scorpio, with the sign each part reaches.
Scope, as the texts state it
BPHS consults the vimsamsa for worship and Narasimha Rao for religious activities and spiritual matters; the page reports both readings and offers no forecast.
Common questions
What is a vimsamsa chart?
The vimsamsa is the D20: every sign split into twenty equal parts of 1 deg 30', the run of parts opening at Aries, Sagittarius or Leo according to whether the divided sign is movable, fixed or dual.
How is the D20 different from the D16?
Both take their starting sign from the three fire signs by quality, and both start movable signs at Aries. The D16 then starts fixed signs at Leo and dual signs at Sagittarius; the D20 reverses those two. The arcs differ as well: 1 deg 52' 30" in the D16, 1 deg 30' in the D20.
Do I need my exact birth time?
For the D20 ascendant, yes. A part covers a degree and a half of the zodiac, so even a small error in the time entered can move the D20 lagna into another sign. Planetary positions change far more slowly and are seldom affected.
Why do Rahu and Ketu share a sign in the D20?
They are six signs apart at the same degree, and opposite signs have the same quality, so both start from one seed and fall in the same part number. The arithmetic puts the two nodes in one D20 sign in every chart; it is not a feature of any particular birth.
Which D20 method does this calculator use?
By default the BPHS count described above. The engine also contains parivritti alternatives, including a cyclic one, but the chart drawn in the divisional charts view is the quality-seeded vimsamsa.