I observe Earth's rotation with an "Optical experiment" every day when I rely on data from polar orbiting earth observation satellites (Sentinel 2A and 2B). Although they go in a polar orbit (as opposed to alongside the equator) what's beneath them changes with each orbit at the exact same rate as Earth's rotation speed.

I would be happy to receive any evidence that the data from these satellites are fake so that I can stop wasting my time (you can find it all here if you're interested). But so far, we're able to use the data to spot forest fires and illegal deforestation, monitor and protect water reserves, and help provide images after natural disasters. So at least it's doing good work for humanity despite being "fake" :)

Have a nice day.