KINGSPORT — Bays Mountain Park is bringing back a double-feature planetarium show this weekend, while highlighting the main feature that's playing through the end of the year. Beginning this Saturday, the planetarium will be showing “Two Small Pieces of Glass” and “Galileo’s Skies,” said Adam Thanz, planetarium director for Bays Mountain. “Two Small Pieces of Glass” looks at 400 years of telescopic discovery, with viewers traveling across time and the globe to witness the people and places that propelled the science of astronomy.