Rahu and Ketu: the shadow planets
Rahu (ராகு) and Ketu (கேது) are not physical planets. They are the two points where the Moon's path crosses the Sun's path across the sky — the lunar nodes. Eclipses happen near these points, which is one reason they have long held a special place in Indian astrology.
Rahu and Ketu always sit exactly opposite each other in a horoscope. If Rahu is in the 1st house, Ketu is in the 7th; if Rahu is in the 2nd, Ketu is in the 8th, and so on. Because of their traditional association with serpents — Rahu as the head and Ketu as the tail — a dosham caused by them is often called Naga dosham or Sarpa dosham (சர்ப்ப தோஷம்).
What is Rahu–Ketu dosham?
Rahu–Ketu dosham refers to Rahu or Ketu occupying houses in the horoscope that are traditionally important for marriage and family life. As with Sevvai dosham, the concern in matching is balance: astrologers prefer that a person with this dosham is matched with a partner whose chart carries a similar influence.
The houses most commonly considered are the 1st (self), 2nd (family), 7th (marriage) and 8th (longevity and shared life). Because Rahu and Ketu are always opposite, Rahu in the 1st or 7th places Ketu in the 7th or 1st, and Rahu in the 2nd or 8th places Ketu in the 8th or 2nd. Some astrologers also look at the 4th, 5th or 12th houses.
Commonly cited cancellations
As with Sevvai dosham, traditional texts and astrologers describe situations in which the influence of Rahu or Ketu is considered reduced. Lists vary, but commonly cited examples include:
- Rahu or Ketu joined with, or aspected by, Jupiter.
- Rahu or Ketu in particular signs that some astrologers consider favourable for them; the signs named vary between traditions.
- Both partners having a similar Rahu–Ketu placement, so the influence is balanced (dosha samyam).
- A good overall balance of malefic points between the two charts, as seen in the பாப புள்ளிகள் (papa pulligal) table in Manavizha's horoscope report.
Rahu–Ketu dosham and Kala Sarpa dosham
These two are often confused. Rahu–Ketu dosham is about which houses Rahu and Ketu occupy. Kala Sarpa dosham is about whether all the other planets are gathered on one side of the Rahu–Ketu axis. A chart can have either one, both or neither. Our separate article on Kala Sarpa dosham explains the difference in detail.
How families usually approach it
Families typically treat Rahu–Ketu dosham the way they treat Sevvai dosham: by checking whether the other horoscope carries a similar influence and whether the overall balance between the two charts is reasonable. When it does not, many families perform a traditional pariharam, such as worship at Thirunageswaram or Sri Kalahasti, which are closely associated with Rahu and Ketu.
As with every dosham, it is worth remembering that astrologers differ on the details and that the dosham is only one part of a horoscope. Manavizha shows dosham and porutham as guidance; a trusted astrologer can read both charts in full, and the decision rests with the couple and their families.
Frequently asked questions
- Is Naga dosham the same as Rahu–Ketu dosham?
- In everyday use, yes. Naga dosham and Sarpa dosham are common names for the dosham caused by Rahu and Ketu, because of their traditional association with serpents.
- Why does the report mention only Rahu, not Ketu?
- Ketu is always exactly opposite Rahu, so Rahu's house also fixes Ketu's. The report checks Rahu's position and the result covers both.
- Should a person with Rahu–Ketu dosham marry someone with the same dosham?
- That is the traditional preference, under the principle of dosha samyam. Many astrologers also look at the total balance of malefic influences rather than one dosham alone.