Astronomy Day Date in the current year: May 18, 2024

The idea of creation of Astronomy Day belongs to Doug Berger, the president of the Astronomical Association of Northern California. He developed his idea and organized the event in 1973. His intention was to set up various telescopes in busy urban locations that the passersby could enjoy the views of the sky. Later the event expanded and number of organizations associated with astronomy became its sponsors.

The original date of Astronomy Day falls on a Saturday between mid-April and mid-May. It was scheduled to occur at or as close as possible to the first quarter Moon. This means that the event of Astronomy Day should be calculated annually.

In 2007 a fall celebration of Astronomy Day was added. The date of the event was scheduled to occur also on a Saturday, but between mid-September and mid-October to be as close as possible to the first quarter Moon.