As Colorado’s oldest standing hotel, the Astor House in Golden has racked up 157 years of stories, including a tale of exploding windows from a Colorado School of Mines detonation across the street — the dynamite was intentional, the broken glass was not — and a man plunging from a second-story doorway onto the ground below. “I’ve heard that when it was a boarding house, they removed the balcony because too many people were spitting tobacco on passersby,” said Hassan Najjar, executive director of Golden’s Foothills Art Center, which reopened Astor House to the public on May 25 after a $4.1 million renovation.