The York County Astronomical Society (YCAS) will offer a public event at its observatory at John Rudy County Park, 400 Mundis Race Road, York, on Saturday, July 20.

From 1 to 3 p.m., YCAS member Kerry Smith will share information about radio astronomy and give attendees a peek into the future of YCAS' radio astronomy endeavors. Radio astronomy is the study of unseen radiated energy in the electromagnetic spectrum below visible light. It allows people to study astronomical phenomena that would otherwise be invisible.

The presentation "How to Buy an Astronomical Telescope" will begin promptly at 1 p.m. and run until 2 p.m. The program will provide information to help members of the public buy an optical astronomical telescope.

Anyone who has a telescope but is not sure how to use it may bring the telescope to the event, and experts will be available to provide assistance from 1 to 2:30 p.m.

The event is free and open to the public. Donations will be accepted to help YCAS continue to bring astronomy-focused events to York County and surrounding areas.

If the weather is clear, all activities will occur as scheduled. If it is completely cloudy or raining, the indoor portion of the event will be available. In the event of extreme weather, cancellation notices will be available by calling 717-759-YCAS (9227) or searching for "York County Astronomical Society (YCAS)" on Facebook.