The "Celestial Horizons: Observing the Sky" experience was a public event held at the Museum of Tomorrow, originally scheduled for November 24, 2017, but postponed to December 2, from 7 pm to 10 pm, due to weather conditions. The free activity invited the public to contemplate the night sky from the museum's pier, proposing a broader reflection on the origin of the universe and humankind, combining scientific knowledge and aesthetic appreciation of the sky. In the company of astronomers, participants could explore questions about the universe while also enjoying the beauty of the Moon, planets, and constellations.

The program began at sunset with a presentation by cosmologist Luiz Alberto Oliveira, then general curator of the Museum of Tomorrow. Following this, astronomers guided the public in identifying celestial bodies and using the five telescopes positioned at the back of the pier for observation. The initiative was a partnership between the Museum of Tomorrow, the Valongo Observatory, the Rio de Janeiro Astronomy Club, and the Rio Astronomy Network.