On June 30th, the National Observatory of Athens and the Youth Cultural Society of Kryoneri hosted an open night for Asteroid Day 2017 at Kryoneri Observatory. Over 400 people attended the event, which included a tour of the 1.2m Kryoneri telescope, viewing of the Moon, planets and other celestial objects through telescopes set up by members of the Hellenic Astronomical Union, and talks by Dr. Bonanos on the danger posed by near-earth asteroids and by Dr. Dapergolas on the Kryoneri telescope.