[enaaem]

In the past astronomers believed in the geocentric model of the universe with epicycles. It was extremely accurate, and if more accuracy was needed they added more epicycles. It was a completely wrong model, but they unknowingly used the Fourier series as a function approximator.

[TeMPOraL]

It wasn't a wrong model, it was just much more complex than needed, given better understanding of physics. Viewing the universe relative to stationary Earth is a perfectly fine exercise, even if it means you have to DFT the rest of the solar system for the math to work.