He also recognised that the orbit of the Moon was inclined to the equator of the Earth and he was one of the first to realise that Venus as an evening star was the same planet as Venus as a morning star.
Siya rin ang kinikilala na ang orbita ng Buwan ay hilig sa ekwador ng Earth at siya ay isa sa mga unang na realise na Venus bilang isang gabi bituin ay ang parehong bilang planeta Venus bilang isang umaga bituin.