# Gītikāpāda I.9 — the Moon's nodes: Rāhu (ascending) and Ketu (descending)
model.geocentric
reset
show.bodies
show.moon
show.moonNodes
show.moonNodeLine
show.eclipticBelt
show.constellations
now
speed.set 15
play
overlay.show The Moon's orbit tilts ~5° to the ecliptic, so the two planes cross along one line
wait 6
overlay.show That line meets the sky at two opposite points — the nodes
wait.next Name them for me

overlay.clear
overlay.show Rāhu, where the Moon crosses going north; Ketu, where it crosses going south
overlay.show Neither is a body. Each is a direction, fixed by the intersection of two planes
wait.next Watch the line itself move

overlay.clear
overlay.show The node line does not hold still — it regresses westward, one full turn in 18.6 years
wait 7
overlay.show So the eclipse seasons creep earlier each year, which is what makes them worth tabulating
wait.next Done

pause
overlay.clear