D60 Chart Calculator (Shashtiamsa)

Sixty slices of half a degree

The arithmetic is short. Ignore the sign, take the degrees a body has travelled inside it, double them and drop the fraction: that is how many whole parts lie behind it, so adding one gives the number of the part it occupies, from 1 at the start of a sign to 60 at the very end. The D60 sign is then found by counting forward from the occupied sign by one less than the part number, wrapping round the zodiac as often as needed.

Take the example's rising degree, Scorpio 11°23′. Doubled, 11°23′ is a little under 23, so twenty-two whole parts lie behind it and the lagna is in part 23. Counting twenty-two signs on from Scorpio passes Scorpio once more and stops at Virgo, so the D60 lagna is Virgo. The degree inside the D60 sign is the distance into the part multiplied by sixty, which is why the example's D60 lagna reads 23°34′.

The verse in the text is brief, and translations differ on where the count of signs begins. Our engine, and so this calculator, counts from the sign the body occupies. A reader who follows a translation that starts the count from Aries will get different D60 signs, though the part numbers and the deities stay the same.

Why the birth time decides the D60

Half a degree of the zodiac is a very small target. The rising degree turns through the whole circle once a day, about one degree every four minutes of clock time on average, so on average it crosses one shashtiamsa every two minutes; the real rate depends on the latitude and on which sign is rising. A birth time rounded to the nearest five minutes can therefore leave the D60 ascendant two or three parts uncertain.

The grahas move far more slowly against the signs. The Moon covers about thirteen degrees a day and stays in one part for roughly an hour; the Sun needs about half a day to cross one; Saturn can sit in the same half degree for a week or more. So a small change in the birth time usually moves the D60 lagna and the houses counted from it, while most of the planets keep their parts. If the result is to be read seriously, the time should be checked first, and the calculator shows each body's degree so that bodies close to a part boundary are easy to spot.

The sixty deities and the even-sign reversal

Parashara gives every part a presiding name. In odd signs the list runs Ghora, Rakshasa, Deva, Kubera, Yaksha, Kinnara, Bhrashta, Kulaghna, Garala, Vahni, Maya, Purishaka, Apampati, Marutvan, Kala, Sarpa, Amrita, Indu, Mridu, Komala, Heramba, Brahma, Vishnu, Maheshvara, Deva, Ardra, Kalinasha, Kshitisha, Kamalakara, Gulika, Mrityu, Kala, Davagni, Ghora, Yama, Kantaka, Shuddha, Amrita, Purnachandra, Vishadagdha, Kulanasha, Vamshakshaya, Utpata, Kala, Saumya, Komala, Shitala, Karaladamshtra, Chandramukhi, Pravina, Kalapavaka, Dandayudha, Nirmala, Saumya, Krura, Atishitala, Amrita, Payodhi, Bhramana and Chandrarekha.

In even signs the same sixty names are read from the other end, so the first half degree of Taurus belongs to Chandrarekha and the last to Ghora. The rule is easy to get wrong in software, because counting signs from zero turns Aries into an even number; the calculator applies the classical parity, in which Aries, Gemini, Leo, Libra, Sagittarius and Aquarius are odd. Several names repeat, Amrita three times and Kala three times, so the part number is the reliable label and the deity is printed beside it.

The text also sorts the deities into gentle and harsh groups. Readers apply that grouping in different ways, and this page reports the names without passing judgement on them.

The weight of the sixtieth division

In chapter 7, where the divisions are weighed against each other for vimsopaka strength, the shashtiamsa carries the largest single share in both of the longer schemes: five of the twenty points in the ten-division scheme and four in the sixteen-division scheme, where the rasi chart itself holds three and three and a half. A planet dignified in its D60 sign therefore gains more in those schemes than from any other single division.

That weight is the reason the D60 is studied at all, and also the reason it is approached with care. A division that counts for so much and changes so quickly is only as good as the time it is built on. Where two charts agree in every coarser division, the D60 is the first division likely to differ between them, and that is exactly the situation in which a few minutes of birth time decide the answer.

The 1961 shashtiamsa, body by body

In the illustrative chart, 13 December 1961 at 05:30 in Channarayapatna with the Lahiri ayanamsa, Saturn at Capricorn 4°17′ is in part 9; Capricorn is even, so its deity is the fifty-second name, Dandayudha, and nine signs counted from Capricorn give Virgo, the same sign as the D60 lagna. The Moon at Aquarius 3°18′ is in part 7 of an odd sign, the part of Bhrashta, and its D60 sign is Leo, the twelfth from the D60 lagna.

Leo also receives Venus, from part 34 of Scorpio under Kalinasha, and Ketu, from part 56 of Capricorn under Yaksha. Rahu sits in part 56 of Cancer, also under Yaksha, and lands in Aquarius beside Mercury, which comes from part 52 of Scorpio under Garala. Mars, in part 56 of Scorpio, falls in Gemini, the tenth house of the D60; the Sun, in part 55 of Scorpio under Kinnara, falls in Taurus, the ninth; and Jupiter, in part 27 of Capricorn under Ghora, falls in Pisces, the seventh.

How is the D60 chart calculated?

Double the degrees a body has travelled in its sign, drop the fraction and add one to get its part, from 1 to 60. Then count that many signs from the occupied sign, starting with the sign itself. The sign you reach is the body's D60 sign.

How accurate does my birth time need to be for the D60?

Very accurate. Each part is half a degree wide, and the rising degree crosses one in about two minutes of clock time on average. A time rounded to five minutes can leave the D60 ascendant uncertain, so check the time before reading the houses.

What are the 60 shashtiamsa deities?

Brihat Parasara Hora Sastra names one deity for each half-degree part, from Ghora in the first part of an odd sign to Chandrarekha in the sixtieth, and reverses the order in even signs. The full list is on this page and the result names the deity of every body.

Why does the deity list run backwards in even signs?

That is how Parashara sets out the shashtiamsa: the sixty names run forward in odd signs and backward in even ones. In Taurus, Cancer, Virgo, Scorpio, Capricorn and Pisces the first half degree therefore belongs to Chandrarekha and the last to Ghora.

Is the D60 the same as the shashtiamsa?

Yes. D60 is the modern shorthand and shashtiamsa, the sixtieth part, is the Sanskrit name, sometimes spelled shastiamsa or shashtyamsa. All refer to the same division of each sign into sixty parts of thirty arc-minutes.

Why does my D60 differ from another calculator's?

Three things usually explain it: a slightly different birth time or ayanamsa moves bodies across half-degree boundaries, some translations start the count of signs from Aries rather than from the occupied sign, and some software reverses the deity order for the wrong signs.