The Connecticut College Department of Physics, Astronomy and Geophysics and the Thames Amateur Astronomical Society will host a celebration of National Astronomy Day on Saturday from 7:30 to 10 p.m. in the Olin Observatory and Science Center.

Binoculars and telescopes will be available to participants, and guest speakers will discuss various aspects of astronomy, including R. M. “Max “ Maxwell, who will explain “How to Use a Star Wheel” at 7:45 p.m. and again at 8:45 p.m.

Lorraine Allen, professor of physics at the U.S. Coast Guard Academy, will present “The Sun’s Dynamic Magnetic Field” at 7:45 p.m. and again at 9:15 p.m.

Leslie Brown, associate professor of physics and astronomy, will deliver “First Contact! Pluto,” a talk on NASA’s New Horizons mission to Pluto, at 8:30 p.m. and again at 9:20 p.m.

The event is free and open to the public. It will proceed as scheduled regardless of clouds or rain.