Ketu: The Significance of Shadow Planet or the South Lunar Node of the Hindu Vedic Astrology

It is considered as headless half planet with neutral sex. It rules the north-west direction as well as Saturday. Smoky-grey color is associated with Ketu and it rules number 7 in Indian numerology. The favorite day is Saturday deity is Lord Ganesh or Vignesh. Its grain is horsegram (khollu); food horsegram rice; flower red lily; metal lead and gemstone is cat's eye (Lasniya).

Significance of Ketu in Vedic astrology

Ketu does not rule any zodiac sign or Rasi. However the zodiacal sign Pisces is considered as Ketu's sign.
Ketu is exalted in zodiacal sign Scorpio. and debilitated in zodiacal sign Taurus. It is benefic in zodiacal sign Libra as well. Mercury, Venus, Saturn, and Ketu are considered as friendly planets and the planets Sun, Moon and Mars are the enemies. Jupiter is neutral. The zodiac signs Gemini, Virgo, Libra, Sagittarius, and Pisces are friendly to Ketu and Cancer and Leo are the enemy signs.

Ruling Star Constellations

Ketu rules star constellations Ashvini, Magha, and Moola or Mula. According to unique Vimsottari Dasa system of Vedic Hindu astrology, for those who have born under these three star constellations, there will be Ketu dasa for 7 years.

Ketu: Benefic and Malefic Influences

Ketu is the ruler of wisdom or gyana or spiritual knowledge, the knowledge of the self powers of discrimination. It is also responsible for your eye sight, wife, children. It is responsible for the provision of health, wealth - land, gold, vehicle, cattle - and prosperity. It helps you to attain fame. It mitigates the sufferings due to snake bites and other poisonous toxins and protects your health. The positive influence of Ketu often helps you to acquire healing powers. The malefic effects of Ketu are explained in ancient texts of Hindu Vedic astrology.

Ketu is afflictive and malevolent unless located in an exalted or powerful position or conjoined with a beneficent planet. The malefic effects of Ketu can be acquiring bad habits, fears of decoity or robbery, putra dosham, loss of property, and loss of face. If Ketu is placed in a disadvantageous position in your horoscope there will be the malefic effects of Ketu which includes failures, heavy loss in business and prolonged frustrations, sorrow, enemity, fear etc.

Yogas and Doshas

Kala Sarpa Yoga' or 'Kala Sarpa Dosha': Your horoscope will be uniquely identified as 'Kala Sarpa Yoga' or 'Kala Sarpa Dosha' when all the planets in your horoscope falls between the axis of Rahu or Ascending Node and Ketu or Descending Node.

'Sarpa Dosha': 1. Starting from Moon if Rahu or Ketu is placed in your 8th house of your horoscope; 2. Starting from your own lagna, if Rahu or Ketu is placed in Trikona (fifth and nineth house).
However if Ketu is placed in an advantageous position in your horoscope you may will be fortunate enough to taste only successes and enjoy the profits and gains and your good influence will turn your enemies as friends. Ketu will alter your strength and power and provide good health, money, happiness etc.

Ketu Mantra

Aum Palasa Puspa Samkasam Tarakagraha Mustakam, Raudram Raudratmakam Ghoram Tam Ketum Phanamam Yaham

Ketu Gayathri

Aum Chitravarnaya Vidhmahe,
Sarparoopaya Dheemahi,
Tanno Ketu Prachodayat

Reference

1)http://lal_kitab.tripod.com/planets/rahu.htm
2)Ketu Effects And Remedies http://www.astrosage.com/lalkitab/LKKetu.asp
3)Ketu Planet , Horoscope http://www.indianetzone.com/2/ketu.htm
4)Ketu Puja http://www.iloveindia.com/spirituality/puja/ketu.html
5)Malefic Effects of Ketu http://jyotisha.00it.com/Ketu.htm
6)Rahu Puja http://www.iloveindia.com/spirituality/puja/rahu.html
7)Sri Kethu Bagavan - Keezhaperumpallam http://www.pondyonline.com/user/NavagrahaTemples/Kethu.aspx
8)Sri Naganathaswamy Temple - Tirunageswaram http://www.pondyonline.com/user/NavagrahaTemples/Rahu.aspx
9)Wikipedia Lunar node http://en.wikipedia.org/wiki/Lunar_node