[lloeki]

Were they incorrect? Seems like they were rather needlessly complex because of the earth-bound parameters.

IOW if you take the simpler heliocentric motion equations and want to make your life miserable by changing the reference frame to be geocentric you'd land up on epicyclic equations.

So even though the math is borne out of a misguided anthropocentric cosmology it does matches reality to a crude but reasonable approximation, unlike a edge-of-disc kraken.

[jl6]

Depends what you mean by incorrect. If the goal is to predict planetary movement, then epicycles might be a useful tool, just like an ocean-bearing moon model might be useful for predicting the wobble of Mimas. But as an explanation of what’s really happening, centering the universe on Earth is not a lot better than positing that kraken.

[lloeki]

Incorrect as in the kraken doesn't exist. The celestial objects do, the equations are valid not just superficially from observation, but deeper as they do encode gravitational laws, if only in a very obscure way due to the reference frame.

A better kraken would be aether theories, whether luminiferous or mechanical gravitational, which survived all the way to the 19th century and mystified Lorentz and Maxwell (esp. the Mickelson experiment results), and even in the 20th initially by Einstein until he gave up on the idea in 1905.