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Can One Measure Lunar Nodal Positions with a Sundial?

-- Dennis | December 29, 2019

Question:

Hello, thanks for reading my question,
How can one determine the lunar nodal points through observation? I do have a large gnomen and have marked out solstice and equinox. I am now studying lunar movement.
Cheers,
Dennis

-- Dennis

Answer:

I can’t think of a way to measure the lunar nodal positions with a sundial. The Moon’s nodal points are where the Moon’s orbit crosses the ecliptic, which is the orbital plane of the Earth. Since the Moon’s orbit is inclined by only 5.14 degrees relative to the ecliptic, you would need to be able to measure the Moon’s shadow on your sundial to better than 5.14 degrees, which would seem to be quite hard to do.

-- Jeff Mangum

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