The York County Astronomical Society (YCAS) is celebrating 16 years offering planetarium programs to the public. YCAS will offer Saturday afternoon programs for young children and families and Saturday evening programs for older family members at the York Learning Center Planetarium, 301 E. Sixth Ave., York.

The children's programs - "One World, One Sky: Big Bird's Adventure" and "Defying Gravity: It Is Rocket Science!" - will be shown at 2 and 3:20 p.m., respectively. For older family members, "Forward! To the Moon" will be shown at 7 p.m., and "Two Small Pieces of Glass" will start at 8:20 p.m. "StarWatch" will be shown at 2:40 and 7:40 p.m.

There is an admission fee, with discounts for children and seniors. Admission to any second or third show will also be discounted. Private show reservations are available. To learn more, visit http://www.astroyork.com.