The co-ordinates in the celestial hemisphere that can cause luni solar eclipse are called rahu and ketu.
Westerners learnt a bit from 'us' and went back. They say the points of intersection of earth's orbit around the Sun and the moon's orbit around the earth, forms 2 points separated by 180 deg and are called lunar nodes. When moon happens to be in any of these nodes, either a solar or a lunar eclipse occurs.
But thats not what we had.
Their reference point of view from where they 'see' the earth, moon, sun and the solar system is somewhere above the solar system plane. If you ask them where are you standing when you are seeing your solar system, thats their reference point.
But our point of reference is the point where we are on earth. If you are lying down on terrace, the reference point is that itself. Our standard meridian was 'Lanka Rekha' the line joining Lanka (not SriLanka), Kanyakumari, Ujjain and Hastinapura (now Delhi). When the solar or lunar eclipse happens, the point of that intersection of sun and moon's apparent path is what we call either rahu or ketu.
If you lie down with you head towards north, sun will move from left to right and so will the moon. Either moon will overlap the sun or earth's shadow will overlap the moon. That point which can cause solar or lunar eclipse is either rahu or ketu.
If after solar eclipse lying down with your hear towards north, if you see moon moving up; if after lunar eclipse you see the shadow clearing up in upward direction - we call that point Rahu.
If you see the moon of solar eclipse or shadow of lunar eclipse move down to clear up the eclipse, we call it Ketu.
So both rahu and ketu cause both solar and lunar eclipse. Westerners have ascending and descending lunar nodes, but are by definition different than our Rahu and Ketu; they are not the same as rahu and ketu.
Due to precession of exquinoxes, these nodes revolve around the earth in direction opposite to moon and sun path at a pace of 30 degres every 19 months.