Astronomy Day is an annual event intended to provide a means of interaction between the general public and various astronomy enthusiasts, groups and professionals.
This event was started in 1973 by Doug Berger, the president of the Astronomical Association of Northern California. His intent was to set up various telescopes in busy urban locations so that passersby could enjoys views of the heavens. Since then the event has expanded and is now sponsored by a number of organizations associated with astronomy.
Astronomy Day also forms part of Astronomy Week, which begins on the preceding Monday.
Astronomy Day occurs on a Saturday between mid-April and mid-May, and is scheduled so as to occur at or just before the first quarter Moon. This means that the event happens on a different date each year, rather than a set calendar date. The table below shows the dates for Astronomy Day: