The eight-period sequence
Bṛhat Parāśara Horā Śāstra 46.195–199 names eight Yoginis, associates them with Moon through Rahu, gives durations from one through eight years, and says to add three to the numbered Janma Nakshatra before dividing by eight. The durations sum to 36 nominal years. Ketu has no separate period in this sequence.
| Yogini | Ruler | Years | Birth nakshatras that open here |
|---|---|---|---|
| 1. Mangala | Moon | 1 | Ardra · Chitra · Shravana |
| 2. Pingala | Sun | 2 | Punarvasu · Swati · Dhanishtha |
| 3. Dhanya | Jupiter | 3 | Pushya · Vishakha · Shatabhisha |
| 4. Bhramari | Mars | 4 | Ashwini · Ashlesha · Anuradha · Purva Bhadrapada |
| 5. Bhadrika | Mercury | 5 | Bharani · Magha · Jyeshtha · Uttara Bhadrapada |
| 6. Ulka | Saturn | 6 | Krittika · Purva Phalguni · Mula · Revati |
| 7. Siddha | Venus | 7 | Rohini · Uttara Phalguni · Purva Ashadha |
| 8. Sankata | Rahu | 8 | Mrigashira · Hasta · Uttara Ashadha |
A person may pass through the cycle more than once. The calculator displays three complete turns, labeled cycle 1 through cycle 3, without treating 108 as a statement about anyone’s lifespan.
Finding the opening Yogini
Number the 27 equal nakshatras from Ashwini as 1 through Revati as 27. Add 3 to that number, then take the remainder after division by 8. Remainders 1 through 7 select Mangala through Siddha; remainder 0 selects the eighth, Sankata.
Use 8 when the remainder is 0.
Ashwini is number 1. One plus three leaves remainder 4 after division by eight, so Ashwini opens with Bhramari, ruled by Mars, for a full nominal length of four years. Rohini is number 4; four plus three gives remainder 7, so Rohini opens with Siddha, ruled by Venus, for seven years. Mrigashira is number 5; five plus three divides evenly by eight, so it opens with Sankata.
Calculating the balance at birth
The opening Yogini names the full period, but most births occur after its conceptual start. The Moon’s progress through its 13°20′ nakshatra gives the elapsed fraction. The untraversed fraction multiplied by the opening period’s years is the balance visible after birth.
Suppose the sidereal Moon is exactly halfway through Anuradha, nakshatra 17. Seventeen plus three leaves remainder 4, so Bhramari is active. Half of Bhramari’s four nominal years has elapsed and two nominal years remain. At the exact starting longitude of a nakshatra, progress is zero and the full opening period remains. At the exact ending longitude, the Moon belongs to the next nakshatra.
The subperiod convention used here
The cited passage specifies the major sequence and refers its birth balance to the earlier elapsed-and-total nakshatra method. It does not state an eight-subperiod formula in those verses. This calculator applies a transparent proportional convention: each major period is divided in the 1:2:3:4:5:6:7:8 ratio, beginning with that major Yogini and continuing around the same cycle.
Inside Ulka’s six-year major period, Ulka/Ulka lasts 6 × 6 ÷ 36 = 1 nominal year. Ulka/Siddha lasts 6 × 7 ÷ 36 = 1.166667 nominal years. The eight subperiods always add back to the parent period. Naming this convention matters because another implementation may omit subperiods or use a different later authority.
Turning nominal years into timestamps
The calculator defines one nominal year as exactly 365.2425 days, the mean Gregorian calendar year, and adds that duration to UTC timestamps. It does not use a 360-day year and does not advance by civil-calendar anniversaries. Every row is a half-open interval: its start instant belongs to that row, while its end instant belongs to the following row. Displayed values round to the nearest second; calculations retain fractional milliseconds.
The local date labels reuse the single UTC offset entered for the birth, even decades later. That keeps every conversion auditable, but it does not reproduce later daylight-saving or political time-zone changes. The ISO value available on each date is the UTC instant.
Moon position and boundary sensitivity
The astronomical layer uses the bundled Astronomy Engine 2.1.19 for the apparent geocentric Moon and the site’s approximate Lahiri conversion. A Moon within 0.1° of a nakshatra edge triggers a notice. The tool also samples the Moon one hour before and after the entered instant and reports when that window crosses an edge. Those checks identify sensitivity; they do not repair an uncertain birth record.
Questions readers ask
Is Yogini Dasha the same as Vimshottari?
No. Both use the birth Moon’s nakshatra, but Yogini uses eight named periods in a 36-year sequence, while Vimshottari uses nine planetary periods totaling 120 years. Their nakshatra-to-period mappings and date scales differ.
Why does Ashwini begin with Bhramari rather than the first Yogini?
The plus-three rule offsets the nakshatra numbering. Ashwini is number 1, and (1 + 3) leaves remainder 4, which maps to Bhramari. Mangala opens for nakshatras whose adjusted number leaves remainder 1, beginning with Ardra.
What happens at an exact period boundary?
The next period begins at that instant. This prevents one moment from belonging to two rows and makes the major and subperiod lookup deterministic.
Text and calculation references
- Bṛhat Parāśara Horā Śāstra, chapter 46, verses 195–199: eight names, planetary associations, plus-three rule, lengths, and birth-balance direction.
- Astronomy Engine 2.1.19: apparent geocentric Moon used before the site’s sidereal conversion.
- Ayanamsa guide: the approximate Lahiri convention used by this site’s Vedic tools.