Rahu and Ketu: the shadow planets
Two points where the Moon's orbit crosses the Sun's path — and the reason eclipses were once explained by a severed demon.
4 min read · Published 22 August 2026
The short answer
Rahu and Ketu are the two lunar nodes — the points where the Moon's orbit crosses the ecliptic. They are not physical bodies but mathematical points, which is why they are called shadow planets or chhaya grahas. Jyotisha treats them as full grahas with their own dasha periods and interpretive weight: Rahu as insatiable worldly desire, Ketu as detachment and past-life residue. They are always exactly 180 degrees apart, and they move backwards through the zodiac.
The astronomy
The Moon's orbit is tilted about five degrees to the ecliptic, the plane of Earth's orbit around the Sun. Any two intersecting planes meet along a line, so the Moon's orbit crosses the ecliptic at exactly two points.
Rahu is the north node, where the Moon crosses going north. Ketu is the south node, where it crosses going south. They are always exactly opposite each other, by definition.
These points matter enormously in real astronomy, because eclipses can only happen near them. A solar eclipse requires a new Moon close to a node; a lunar eclipse a full Moon close to one. Away from the nodes the Moon passes above or below the alignment and nothing happens.
They also drift backwards — retrograde — through the zodiac, completing a circuit in about 18.6 years.
What Jyotisha does with them
| Rahu (north node) | Ketu (south node) | |
|---|---|---|
| Traditional image | The severed head — appetite without a body | The headless body — action without appetite |
| Associated with | Worldly desire, ambition, obsession, the unfamiliar | Detachment, spirituality, loss, past-life residue |
| At its best | Drive toward what you did not inherit; innovation | Renunciation, insight, expertise carried in without learning |
| Unchecked | Insatiability; never enough; deception | Disengagement; dismissing what matters |
| Dasha length | 18 years | 7 years |
Both have their own dasha periods — Rahu's eighteen years is one of the longest in the Vimshottari sequence — and both rule three nakshatras each. They are treated as full participants in the system, not as minor points.
How Western astrology treats them differently
Western astrology has the same two points and gives them far less weight.
They appear as the North and South Node, and modern practice reads the north node as a growth direction and the south node as inherited patterns — a broadly karmic reading that entered Western astrology relatively recently, and which is where past-life interpretations usually attach.
But no Western system gives them ruling periods, or treats them as full planets with the interpretive weight of Mars or Saturn. In Jyotisha they are grahas; in Western astrology they are points.
There is also a technical difference: Western astrology commonly uses the mean node, a smoothed average, while some Vedic practice uses the true node, which wobbles. The two can differ by over a degree.
The eclipse connection is the interesting part
The nodes are one of the few places where astrological symbolism and real astronomy line up in a way that is genuinely satisfying rather than coincidental.
A tradition that treats these two points as devouring the Sun and Moon is describing, in mythological language, the exact geometric condition under which eclipses occur. The story is not an arbitrary decoration attached to an abstract point — it encodes an observation.
That does not make the interpretive claims about ambition and detachment true. It does mean the nodes are a case where the tradition was tracking something real, which is worth acknowledging honestly. Every eclipse in AsterNym's 2026 and 2027 calendars happens because the Moon was near one of these two points.
Where to find yours
AsterNym computes the mean lunar nodes on your natal chart — north and south, always opposite, with their signs and houses. That is the same astronomical pair Jyotisha calls Rahu and Ketu, before an ayanamsa is applied.
For the Vedic reading — their nakshatras, their dashas, their interpretation within a sidereal chart — you want a Jyotisha tool. We compute the positions and label the karmic interpretation as interpretation rather than as a finding.
Common questions
- What are Rahu and Ketu?
- The two lunar nodes — the points where the Moon's orbit crosses the ecliptic. Rahu is the north node and Ketu the south. They are mathematical points rather than physical bodies, which is why they are called shadow planets, and they are always exactly 180 degrees apart.
- Why are Rahu and Ketu connected to eclipses?
- Because eclipses can only occur when a new or full Moon happens near a node. Away from the nodes the Moon passes above or below the alignment. The myth of Rahu swallowing the Sun and Moon encodes exactly this geometric condition.
- What do Rahu and Ketu mean in a chart?
- Jyotisha reads Rahu as worldly desire, ambition and obsession with the unfamiliar, and Ketu as detachment, spirituality and residue carried from a previous life. Rahu has an eighteen-year dasha period and Ketu seven.
- Does Western astrology use Rahu and Ketu?
- It uses the same two points, called the North and South Node, but gives them much less weight — as points rather than full planets, with no ruling periods. The modern Western reading of north node as growth direction and south node as inherited pattern is a relatively recent addition.