A Navamsa, or D9 chart, is made by dividing each 30° sidereal rāśi into nine equal 3°20′ parts. It is a chart of transformed longitudes. The D9 diagram does not show planets at a second sky time, and it should be read alongside the original D1 positions and their calculation settings.
How the sign sequence is assigned
There are 12 rāśis × 9 divisions = 108 Navamsa segments around the full zodiac. Number those segments from zero at 0° sidereal Aries. Divide a position's sidereal longitude by 3°20′ and take the whole-number segment index. Its D9 sign is the index modulo twelve, beginning with Aries. Within that resulting sign, the fractional part of the segment is scaled to 0°–30°. At the exact 3°20′ boundary, the next segment begins.
Traditional instructions express the same cycle by sign type. For movable signs (Aries, Cancer, Libra, Capricorn), begin the nine D9 signs from the rāśi itself. For fixed signs (Taurus, Leo, Scorpio, Aquarius), begin from the ninth sign from it. For dual signs (Gemini, Virgo, Sagittarius, Pisces), begin from the fifth. The Bṛhat Parāśara Horā Śāstra rule reproduced by SIA Vigyan states this movable/fixed/dual pattern. The formula here implements that sign assignment; it does not borrow another site's output table.
Two boundary examples
A point at 0°00′ sidereal Aries begins D9 Aries. A point exactly at 3°20′ Aries begins D9 Taurus; one arcsecond before that is still in the Aries D9 segment. Taurus begins at 30° of the full zodiac, the tenth segment, so 0°00′ Taurus begins D9 Capricorn. The sequence and every boundary can be checked without an interpretation of the person's life.
Why the birth time matters more for the D9 Lagna
The ascendant depends on the birth moment and place. The D1 rising sign spans 30°; each D9 segment within it spans only 3°20′. A clock or historical UTC-offset error that leaves the D1 sign unchanged can still alter the D9 Lagna. A date-only chart cannot establish that Lagna. This site's D9 calculator therefore requires a recorded time, latitude, longitude, and offset rather than filling in a guessed noon value.
Moon and other faster-moving positions can also cross a D9 boundary during a civil day. The tool reports the calculated UTC instant, approximate Lahiri ayanamsha, D1 sign and degree, D9 sign and derived degree, and a close-boundary warning. Compare those inputs before comparing a result with Prokerala's public D9 chart or a different setting in another Jyotish program.
How this free chart differs from a complete Jyotish report
The page transforms the seven classical grahas plus mean Rahu and Ketu calculated for the D1 chart. It shows a South Indian fixed-sign D9 layout and marks a D1/D9 same-sign match. It does not supply dosha, strength, marriage, compatibility, or event predictions. The historical literature contains different interpretive uses for divisional charts; a computed sign is a mathematical result, while an interpretation requires a named source and judgement.
This website uses Astronomy Engine and an independently coded approximate Lahiri conversion, not the Swiss Ephemeris. Near a D9 boundary, differences in ayanamsha, ephemeris, birth time, or location can change the sign. The supported local birth-date input range is 1800–2100, and users must provide the historical time-zone offset themselves. These limits matter especially for a ninefold chart.