RICHMOND HILL, Ont. – Saturday is International Astronomy Day, where people across the world celebrate all things astronomical.

If you’re looking to join in the celebrations, the David Dunlap Observatory (DDO) in Richmond Hill is marking the day with a number of activities.

The events begin at 4 p.m., when kids will be able to build alien puppets while learning about the sun.

Visitors will also, weather permitting, be able to look at the sun through solar telescopes.

The afternoon program wraps up at 7:00 p.m., and, again, weather permitting, the observatory will re-open at 9 p.m., when people will be able to gaze at the stars through the big telescope.

There will also be volunteers from the Royal Astronomical Society of Canada with a variety of smaller telescopes set up.

Located at 123 Hillsview Drive in Richmond Hill, the DDO first opened in 1935.

With the largest optical telescope in Canada, the DDO is the biggest volunteer-managed observatory in the world.

You can find more information here.