Meaning
Rahu is a point, not a body: the ascending node of the Moon, where its orbit crosses the Sun's path going north. Eclipses happen when the Sun and Moon are near the nodes, and Jyotisha counts the two nodes as grahas, "seizers", beside the seven visible ones.
The story behind the name is the churning of the ocean: the demon Svarbhanu drank the nectar of immortality among the gods, the Sun and Moon gave him away, and Vishnu cut off his head, which as Rahu still chases them and swallows them at eclipses. We tell it as lore; the astronomy underneath it is real. The Brihat Jataka names Rahu Tama, "darkness", and Asura, and gives it the south-west.
It moves backwards through the zodiac, a full circuit in about 18.6 years, always opposite Ketu. Modern readings make it the graha of ambition and appetite, the foreign and the unconventional, obsession and illusion. Our chart writes it Ra and uses the mean node, as the official Rashtriya Panchang does, with the true node, up to about 2° away, as an option.
Rashis and dignities
Rahu rules no rashi in the Brihat Jataka, and the text's verses on exaltation and debilitation name the seven visible grahas only; al-Biruni wrote in 1029 that Indian astrologers did not recognise exaltations of the nodes. Two later schemes, Vrishabha or Mithuna for Rahu, are both in use, and we show neither as fact. Many give the nodes the drishti of Guru, on the fifth, seventh and ninth rashis, which is disputed. It is the Vimshottari lord of Ardra, Swati and Shatabhisha.
Its period
In the Vimshottari dasha Rahu holds eighteen of the cycle's 120 years, the sixth period in the order Ketu, Shukra, Surya, Chandra, Mangala, Rahu, Guru, Shani, Budha. A person whose Moon stands in Ardra, Swati or Shatabhisha at birth begins life in Rahu's period, counting only the part still to run; for any other Moon it comes later in the sequence. Each period is divided into nine sub-periods in the same order.
Our chart's reading of the period, in our words: "The eighteen-year Rahu mahadasha often brings strong ambition, unconventional paths and an appetite for new experiences. It can stir restlessness and a desire for more, and a clear sense of values helps channel its intensity." The tradition's reading of this period, not a prediction of events, and not advice on health, money, legal matters or relationships. The dates follow the chart's conventions, years of 365.25 days and the Lahiri ayanamsa; other tools differ from ours by days.
Correspondences
Each item with how it stands: “sourced” is in the work cited, “our construction” is EsoTerrier’s own, and “disputed” means the sources disagree.
- Names in the Brihat Jataka (II.3)
- Tama (darkness), Agu, Asura sourced
- Natural nature
- malefic in later tradition; the Brihat Jataka's list leaves the nodes out sourced
- Exaltation
- Vrishabha, or Mithuna, in two later schemes; neither in the Brihat Jataka disputed
- Node
- the mean node by default; the true node, up to about 2° away, as an option sourced
- Themes in modern readings, our summary
- ambition and appetite, the foreign and the unconventional, illusion our construction
How the schools read it
- The Brihat Jataka (Varahamihira, 6th century; Iyer 1885)
- Named Tama, "darkness", and Asura; given the south-west; no rashi, exaltation or nature in the verses on the seven grahas.
- The Brihat Parashara Hora Shastra, as printed
- Eighteen years in the Vimshottari order; the lord of Ardra, Swati and Shatabhisha.
- Modern Jyotisha
- Ambition and appetite, the foreign and the unconventional, illusion.
- True-node users
- The osculating node, up to about 2° from the mean (1.95° at most between 1950 and 2050); some Indian software defaults to it.
- Western tropical astrology
- The North Node of the Western chart, which usually takes the true node; the same point measured from the equinox.
- EsoTerrier
- Shown as Ra in the boxes, with its degree; retrograde always, as the tradition reads the nodes.
Claims about it
-
The dasha of this graha foretells events to the day.
unverifiedWhat the record shows: Dasha dates move with the ayanamsa, the year length and the Moon's degree; tools differ by days. We give the period with its conventions stated, as the tradition's theme for a stretch of years.
-
This graha's place foretells illness, wealth or marriage, and doshas cause misfortune.
unverifiedWhat the record shows: These are claims of the tradition and of the commercial kundli. We compute no doshas.
-
Rahu and Ketu are the severed head and body of a demon who swallows the Sun and Moon.
told as loreWhat the record shows: The story explains eclipses. Rahu and Ketu are the Moon's nodes, the two points where its path crosses the Sun's; eclipses happen when the Sun and Moon are near them.
-
Rahu and Ketu have exaltation rashis.
disputedWhat the record shows: The Brihat Jataka gives exaltations for the seven visible grahas only, and al-Biruni recorded in 1029 that Indian astrologers did not recognise exaltations of the nodes. The two modern schemes (Vrishabha and Vrishchika, or Mithuna and Dhanu) are later; we show neither as fact.
-
Only the mean node (or only the true node) is the correct Rahu and Ketu.
disputedWhat the record shows: Both are conventions, up to about 2° apart. The official Rashtriya Panchang tabulates the mean node; some tools default to the true one. Ours uses the mean node, labelled, with the true node as an option.
Elsewhere on EsoTerrier
- Nakshatra 6: Ardra a nakshatra it rules as Vimshottari lord
- Nakshatra 15: Swati a nakshatra it rules as Vimshottari lord
- Nakshatra 24: Shatabhisha a nakshatra it rules as Vimshottari lord
- Graha 9: Ketu, the south lunar node the other node, always opposite
- Natal Chart (Tropical): the North Node the Western chart's lunar node
