Sun-Moon yoga
A Sun-Moon yoga is a measure of the moment taken from the Sun and the Moon together. Where a tithi (lunar day) looks at how far apart the two are, the Sun-Moon yoga adds their longitudes. There are 27 of them, from Vishkambha to Vaidhriti, and the one running at a birth is one of the five limbs of the panchaanga, hora's almanac of the moment.
Adding the Sun and the Moon
Take the Sun's longitude and the Moon's, both in the nirayana (sidereal) zodiac, and add them. The sum can reach almost 720°; when it passes 360°, take 360° away, so it goes round the circle once only. Then cut the circle into 27 equal parts of 13°20′, the same length as a nakshatra (lunar mansion): a sum from 0° to 13°20′ is the first Sun-Moon yoga, Vishkambha, one from 13°20′ to 26°40′ the second, and so on, up to Vaidhriti, the 27th, which ends at 360°.
Both bodies move forward, so the sum always grows, at the Sun's speed plus the Moon's, a little over 14° a day. A Sun-Moon yoga therefore usually lasts a little less than a day, and, like a tithi, can start and end at any hour.
Not a yoga of grahas
Later in the book, in chapter 11, the word yoga means something else: a combination of grahas (planets) in a chart, such as two of them in the same house, that is read for a particular result. Those yogas are patterns of placement and many can be present in one chart at once. The Sun-Moon yoga is just a number from the sum of two longitudes, and exactly one of them runs at any moment. To keep the two apart, hora always calls this one the Sun-Moon yoga.
The table
The table gives the same facts as the book's Table 5: each Sun-Moon yoga's number, its name and what the name means.
| Number | Sun-Moon yoga | Meaning |
|---|---|---|
| 1 | Vishkambha | Door bolt, supporting pillar |
| 2 | Preeti | Love, affection |
| 3 | Aayushmaan | Long-lived |
| 4 | Saubhaagya | Good fortune, long life of the spouse |
| 5 | Sobhana | Splendid, bright |
| 6 | Atiganda | Great danger |
| 7 | Sukarman | One who does good deeds |
| 8 | Dhriti | Firmness |
| 9 | Shoola | Shiva's weapon of destruction (pain) |
| 10 | Ganda | Danger |
| 11 | Vriddhi | Growth |
| 12 | Dhruva | Fixed, constant |
| 13 | Vyaaghaata | Great blow |
| 14 | Harshana | Cheerful |
| 15 | Vajra | Diamond (strong) |
| 16 | Siddhi | Accomplishment |
| 17 | Vyatipaata | Great fall |
| 18 | Variyan | Chief, best |
| 19 | Parigha | Obstacle, hindrance |
| 20 | Shiva | Lord Shiva (purity) |
| 21 | Siddha | Accomplished, ready |
| 22 | Saadhya | Possible |
| 23 | Subha | Auspicious |
| 24 | Sukla | White, bright |
| 25 | Brahma | The creator (good knowledge and purity) |
| 26 | Indra | Ruler of the gods |
| 27 | Vaidhriti | A class of gods |
A worked example
On 1 January 2000 at 12:00 UT, at Greenwich, hora places the Sun at 16°31′17″ in Sagittarius, a longitude of 256°31′17″, and the Moon at 19°28′14″ in Libra, a longitude of 199°28′14″ (see the chart; the rasi page shows how a position in a rasi becomes a longitude).
- The Sun plus the Moon is 256°31′17″ + 199°28′14″ = 455°59′31″. That is more than 360°, so take 360° away: 95°59′31″.
- Seven parts of 13°20′ make 93°20′, which leaves 2°39′31″: seven Sun-Moon yogas are complete, so the eighth is running, and the sum has 10°40′29″ still to grow before it ends.
- In the table, number 8 is Dhriti.
In the chart
The panchaanga on the chart page gives the Sun-Moon yoga at the birth, with its number in brackets; its value there links to this page. The table under it tells when that Sun-Moon yoga started and when it ends.
Next comes the karana: the half of a tithi, the last of the panchaanga's limbs.
Book reference: P.V.R. Narasimha Rao, Vedic Astrology: An Integrated Approach, chapter 1, § 1.3.9. Where to get the book