Siddhamsa D24 Calculation: 24 Parts, Two Cycles and Exact Boundaries

How do you calculate a Siddhamsa D24 sign?

Siddhamsa is also called Chaturvimsamsa. The cited Parashari rule supplies the starting signs; the examples below show how to apply it. This is also the sign-assignment convention in Astrogyana's Vargas calculation. Keep the rule with the result when comparing reports.

One part is 1.25°, not 1.15°

The exact width is 30° ÷ 24 = 1.25° = 1°15′ = 75 arcminutes = 4,500 arcseconds. A decimal value of 1.15° means 1°09′. Using it as the part width moves the boundaries and produces a different table.

Let d be the degree inside the natal sign, from 0° up to but excluding 30°. Part one includes 0° and stops just before 1°15′. Exactly 1°15′ starts part two. Exactly 15° starts part thirteen. At 30°, first move into the next natal sign and recalculate its parity.

Odd means Aries, Gemini, Leo, Libra, Sagittarius or Aquarius: sign numbers 1, 3, 5, 7, 9 and 11. Even means Taurus, Cancer, Virgo, Scorpio, Capricorn or Pisces. It does not refer to an odd degree, a weekday or the house number.

The full lookup: twelve rows cover all 24 parts

Choose the interval containing d, then use the column matching the natal sign's parity. Lower endpoints are included; upper endpoints are excluded. For example, d = 18° lies in the second interval of row three. Its destination is Libra for every odd natal sign and Virgo for every even natal sign.

The two intervals in a row begin 15° apart. Twelve parts use 12 × 1°15′ = 15° and complete one zodiac cycle. Parts thirteen through twenty-four repeat the destinations of parts one through twelve. This repetition is a useful cross-check, not a second optional calculation method.

Calculate from a full longitude in four steps

1. Normalize the full sidereal longitude to 0° ≤ L < 360°.
2. Identify the natal sign and subtract its starting longitude to obtain d.
3. Divide d by 1.25°, discard the fractional part and add one to obtain the part number p.
4. Start at Leo for an odd natal sign or Cancer for an even one; move forward p − 1 sign positions.

For the invented longitude 286°15′, Capricorn begins at 270°, leaving d = 16°15′. Thirteen complete 1°15′ intervals have passed, so p = 14. Capricorn is even: start at Cancer and advance thirteen places, which gives Leo. Counting Cancer as the first destination gives the same answer.

If using zero-based sign indices, Aries = 0 and Pisces = 11. With q = floor(d ÷ 1.25), the destination index is (start + q) mod 12, where start is 4 for an odd natal sign and 3 for an even one. Sign numbers and array indices differ by one; do not mix them.

Ten positions to test boundaries and repetition

The positions 241°14′59″ and 241°15′00″ differ by one arcsecond but cross a part boundary. The pair at 254°59′59″ and 255°00′00″ crosses from part twelve to part thirteen. The count continues while the destination sequence returns to Leo.

Compare 243° and 258°. Both are in Sagittarius, and they differ by 15°. Their parts are three and fifteen, yet both produce Libra in D24. The final row treats 360° as 0° Aries before applying the odd-sign rule.

Can D1 and D24 recover the original degree?

They narrow it to two intervals under this rule. They do not identify a unique degree. If the natal sign is Sagittarius and the D24 destination is Libra, row three gives 2°30′ ≤ d < 3°45′ or 17°30′ ≤ d < 18°45′. The invented 3° and 18° positions both fit.

For Capricorn with D24 Leo, the alternatives are 1°15′ ≤ d < 2°30′ and 16°15′ ≤ d < 17°30′. Knowing that the starting column is even removes neither interval. A displayed D24 sign therefore cannot reconstruct an exact longitude or certify an exact birth time.

This is a different information limit from D12's single cycle. Always count how often a destination occurs before trying to invert a divisional table.

Check a report without overreading the arithmetic

Use the same sidereal reference, input longitude and assignment convention in both reports. Preserve unrounded coordinates near a boundary: a display rounded to 16°15′ may conceal a value just below it. Extra printed decimals do not improve uncertain birth data.

A D24 destination is a sign. A house label additionally needs the D24 ascendant and the stated house convention. To calculate that ascendant's sign, apply the same division rule to the natal ascendant longitude. Do not read “part fourteen” as a fourteenth house.

Use the Kundli report to inspect the inputs and placements, and compare the different assignment logic in D4 or D7. Correct arithmetic establishes consistency with a declared convention; it does not measure intelligence or predict an examination result.

Frequently asked questions