Rahu and Ketu, the North and South Nodes of Moon are referred to in Jyotisha as chaya grahas or shadow planets because they have no physical existence of their own like other planets.
They are more like a shadow or an energy vortex, which get influenced by other factors and they even behave as magnifiers towards the qualities of planets or signs they are together with (especially Rahu).
This give them a special ability to form Raja yogas and give the results like that of Raja yogas in their Dasa (planetary period) or Antar-dasa (sub-period). The following verses from Brihat Parasara Hora explains Raja yogas by Rahu and Ketu.
Classical verse translated
“The shadow planets, Rahu and Ketu, give predominantly the effects of the lord of the house with whom they are in conjunction or of the house are situated.”
This makes Rahu and Ketu capable of inheriting the good attributes of angle or trine lords, when placed in an angle or a trine house.
“If the shadow planets, Rahu and Ketu, are situated in an angle or a trine, are in a conjunction with or are aspected by the angular lord or the trine lord, then they are Yoga Karakas.”
The above verse gives two variation and four type of possibilities for Rahu and Ketu to form Raja yogas.
- If Rahu or Ketu are in an angle house, and are either conjunct or aspected by a trine lord, they give Raja Yog.
- If Rahu or Ketu are in a trine house, and are either conjunct or aspected by a trine lord, they give Raja Yog.
See,
Raja Yogas
Yoga karakas