Really? Why would God place a commandment on His people when they could not perform it properly? Clay calendars go back to Moses day showing the seventh day. Did Moses keep the real Sabbath , being as he met God face to face and received the Ten Commandments? Did Jesus keep the real Sabbath? You're saying something is too hard for you to do when the proof is tight there on your calendar. Why do we keep a 7-day week? It has nothing to do with celestial events, but only because God instituted it.
I reassert my original point. The 7th day that God rested as described in Genesis is lost to antiquity.