Sibling comments say/explain how it is done 'properly', but surely you could just 'lock to the ground' and then animate it flipping 'in post'? It's not like we need the fancy camera mounts to know how the rotation goes?
The linked source names the mount used, the Sky-Watcher Star Adventurer, but yes, you could replicate this in post, except that the frames have exposure times of up to 45 seconds, which would give star trails within individual frames.
Wouldn't the equatorial mount prevent star trails? I guess you could compensate with a shorter exposure time, and perform the rotation in post. I assume it's only possible to do from some angles of the sky.