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Rahu

Rahu graha
Rahu graha Image: Wikimedia Commons. E. A. Rodrigues / Public domain

Overview

Rāhu (Sanskrit: राहु) is one of the nine major celestial bodies, or navagraha, recognised in Hindu texts. He is described as the king of meteors and represents the ascension of the Moon in its precessional orbit around the Earth, also referred to as the north lunar node. Along with his counterpart Ketu, Rahu is classified as a "shadow planet" believed to be responsible for eclipses. Although Rahu has no physical existence as a body in the modern astronomical sense, ancient seers allocated him the status of a planet within the navagraha framework owing to the strong influence ascribed to him in astrology.

In traditional Hindu astrology, Rahu is almost always paired with Ketu, the south lunar node. The two are conceptualised as complementary points in the celestial sphere, and many doctrines, rituals and observances associated with Rahu cannot be discussed in isolation from those associated with Ketu. The portion of the day considered to be under Rahu's influence is called Rāhu kāla and is regarded as inauspicious in popular practice.

Background

The conception of Rahu in Hindu thought reflects an integration of astronomical observation with mythic personification. Astronomically, Rahu and Ketu denote the points of intersection of the paths of the Sun and the Moon as they move on the celestial sphere. These two points are the lunar nodes: Rahu is the personification of the north lunar node and Ketu the personification of the south lunar node. Eclipses occur when the Sun and the Moon are at or near one of these points, a phenomenon explained in traditional accounts as the swallowing of the Sun or the Moon by a serpent-like figure.

According to this understanding, when the Sun conjoins either node on the ecliptic, the new moon obscures sunlight, causing a solar eclipse, while at the full moon the Earth's shadow obscures lunar light, resulting in a lunar eclipse. The narrative imagery of a celestial being swallowing the luminaries thus aligns with the observed astronomical event of an eclipse, and this dual character — astronomical phenomenon and mythic personification — is a defining feature of Rahu in Hindu tradition.

Hindu astrology assigns Rahu and Ketu an orbital cycle of approximately 18 years, and the two are always positioned 180 degrees apart, both in the sky and in birth charts. This figure coincides with the precessional cycle of the Moon, that is, the roughly 18-year rotational cycle of the lunar ascending and descending nodes on the Earth's ecliptic plane. The same period also corresponds to a saros, a cycle of approximately 223 synodic months (about 6585.3211 days, or 18 years, 11 days and 8 hours), which can be used to predict eclipses of the Sun and the Moon. The convergence of mythic accounts with this measurable astronomical periodicity has made Rahu a recurring subject of both religious and astronomical commentary.

Career or topic context

Within the navagraha system, each of the nine bodies is associated with particular signs of the zodiac, nakshatras (lunar mansions) and qualities. Rahu rules the zodiac sign of Aquarius together with Shani (Saturn), who is the traditional ruling planet of that sign. The nakshatras assigned to Rahu in classical astrological texts are Ardra, Swati and Shatbhisha. These associations form the basis of how astrologers interpret the placement of Rahu in a horoscope and how its influence is read in relation to the other grahas.

The notion of Rāhu kāla, a daily window of time considered inauspicious for beginning new ventures, is widely observed in popular practice. Devotees and practitioners often consult almanacs (panchangas) to determine the period of Rahu kāla for any given day, and many avoid commencing important activities such as travel, ceremonies or business transactions during that interval. Such observances draw upon the astrological status of Rahu as a shadow planet of strong, often disruptive, influence.

Beyond daily timing, Rahu features in numerous rituals associated with eclipses. Because eclipses are traditionally explained through the imagery of Rahu seizing the Sun or the Moon, the periods of solar and lunar eclipses are regarded as spiritually significant, and a range of practices — including bathing, fasting, recitation and charitable giving — are commonly associated with them. The pairing of Rahu and Ketu, separated by 180 degrees and tied to the lunar nodes, ensures that both figures are invoked together in many of these contexts.

Significance

Rahu's significance in Hindu tradition derives from the manner in which an observable astronomical phenomenon — the lunar nodes and the eclipses occurring at them — has been integrated into a wider cosmological and religious framework. As one of the navagraha, Rahu is part of a system that links the heavens to the experience of time, fortune and ritual life. The presence of Rahu and Ketu in the navagraha alongside the Sun, Moon, and the visible planets indicates the importance accorded to the lunar nodes in Indian astronomical and astrological reasoning, even though they do not correspond to physical bodies.

The continued use of Rāhu kāla in everyday timing decisions, the observance of eclipse-related rituals, and the place of Rahu in birth-chart interpretation all reflect the enduring cultural reach of these ideas. The same configuration also connects Hindu astrological tradition with broader astronomical knowledge, since the saros cycle and the precessional motion of the lunar nodes are recognised in modern astronomy as the basis for predicting eclipses. Rahu thus stands at the intersection of myth, ritual practice and observational astronomy within Hindu traditions.

Editorial review notes

This draft has been prepared from limited source notes drawn from the English Wikipedia article on Rahu and is intended for review and rewriting by human editors before any publication on IndiaWiki. The following points may assist reviewers:

  • The article presents traditional beliefs as elements of Hindu textual and astrological traditions, rather than as factual claims about the physical world. Editors should preserve this neutral framing and may wish to clarify further where appropriate, particularly when discussing the "swallowing" of the Sun and the Moon during eclipses.
  • Specific iconographic, regional and sectarian variations in the depiction and worship of Rahu are not covered in the source notes provided. Editors with access to additional reliable sources may consider expanding the article with material on temple traditions, iconography, regional festivals, and references in Puranic literature, taking care to cite each addition.
  • The astronomical figures cited — the approximate 18-year nodal cycle and the saros of about 6585.3211 days — should be cross-checked against authoritative astronomical references before publication.
  • Mythological narratives concerning the origin of Rahu, including accounts associated with the churning of the ocean, are not included here because they were not provided in the source notes. Editors are encouraged to add such material from properly cited textual sources rather than from generalised retellings.
  • The list of nakshatras associated with Rahu (Ardra, Swati and Shatbhisha) and the rulership of Aquarius shared with Shani are taken directly from the source notes and should be verified against standard astrological texts.

References

  • "Rahu", English Wikipedia, https://en.wikipedia.org/wiki/Rahu (source notes used for this draft).
  • Editorial note: additional citations to primary Hindu textual sources, panchanga literature, and standard works on Indian astronomy and astrology should be added by reviewers prior to publication.