What system, besides Copernicus's, was considered a viable explanation for the known observations at the time Galileo made his discoveries?

Answer

The Tychonic system

The Tychonic system, where planets orbit the Sun but the Sun and stars orbit the stationary Earth, explained the observations available at that time just as well as Copernicus's model did.

What system, besides Copernicus's, was considered a viable explanation for the known observations at the time Galileo made his discoveries?
Galileoastronomysciencesolar systemheliocentrism