The Chester County Astronomical Society was formed as a non-profit organization dedicated to the education and enjoyment of astronomy for the general public. The Society holds meetings (with member or guest speakers) and observing sessions once a month. Anyone who is interested in astronomy is welcome to attend meetings and become a member of the Society. In addition to the monthly meetings and observing sessions, the Society also provides a variety of services to the public, including astronomy classes as well as telescopes and expertise for "star parties" for school, scout, and other civic groups.

• Tuesday, February 10, 2026 - CCAS Monthly Meeting in Room 112, Merion Science Center, WCU (as well as via Zoom). The meeting starts at 7:30 PM, EST. Guest Speaker: Dr. Becca Phillipson, Assistant Professor in the Department of Physics at Villanova University. The presentation is titled "Chaos in the Cosmos!" and will commence at approximately 8:00 PM EST.
• Thursday, March 5,2026 - STEM night at Greenwood Elementary School, Kennett Square, 6:00 to 8:00 PM EST.
• Saturday, March 7,2026 - Coatesville Star Party, Hibernia County Park, Parking at pavilion #5 lot, 6:00 to 10:00 PM EST.

Jupiter is at its biggest and brightest all year, the Moon and Saturn pair up, and the Beehive Cluster buzzes into view. Additional information about topics covered in this episode of What's Up, along with still images from the video, and the video transcript, are available at https://science.nasa.gov/skywatching/whats-up/

For star parties and astronomy events near you, visit http://nightsky.jpl.nasa.gov/. Learn about all of NASA's missions at http://www.nasa.gov/.

When NASA’s Pioneer 10 and Pioneer 11 spacecraft passed about 20 astronomical units from the Sun, scientists noticed something strange: both probes seemed to experience an unexplained acceleration back toward the Solar System. For years, the “Pioneer Anomaly” sparked serious debate. Some researchers even wondered if it hinted at new physics, flaws in gravity, or unexpected cosmic effects. But decades later, a much more grounded explanation emerged — one involving heat, radiation, and the spacecraft themselves. In this video, we break down what really happened to NASA’s Pioneer probes, why the anomaly confused scientists for so long, and how the mystery was finally solved.

Visit our website for up-to-the-minute updates: www.nasaspacenews.com.

The society schedules monthly observing sessions in the Myrick Conservation Center of the Brandywine Red Clay Alliance. The observing sessions, which are planned around the new moon, are open to the public and announced in the Society's newsletter, Observations. Owning a telescope or binoculars is not required; anyone interested in observing the heavens is welcome to show up. If you do have a telescope and need help using it, our observing sessions are a great place to practice and learn from other society members.

The Chester County Astronomical Society's regular monthly meetings include a presentation from an invited speaker or the demonstration of an astronomical project by one of the Society's members. After the presentation, a brief business session is held to review the status of society activities. Meetings typically last 1-1/2 to 2 hours including an informal conversation over refreshments before the start of each meeting.

The Society meets at 7:30 PM the second Tuesday of each month in the Merion Science Center (former Boucher Building) at West Chester University (corner of South Church Street and Rosedale Avenue, West Chester, Pennsylvania). Click for Directions and Maps.

The Chester County Astronomical Society offers "nights out" to interested organizations including local schools, scouting groups, and other civic groups for the purpose of learning more about the heavens. For example, scouting groups often hold them to earn badges for their members. If your organization is interested in hosting a "night out", please contact us.

• Thursday, March 5,2026 - STEM night at Greenwood Elementary School, Kennett Square, 6:00 to 8:00 PM.
• Saturday, March 7,2026 - Coatesville Star Party, Hibernia County Park, Parking at pavilion #5 lot, 6:00 to 10:00 PM.

Star parties are national and regional events similar to "nights out" and open to the public. They are held throughout the year. For a list of upcoming national events in 2026, visit the star parties page.

The West Chester University Department of Geology & Astronomy hosts a planetarium show open to the general public on the 2nd Friday of each month. The WCU Planetarium is located in the Schmucker Science Center on Church St. To locate the planetarium, view the campus map.


The shows start promptly at 7:00 P.M. ET and run approximately one hour in length. Late arrivals will not be permitted to enter the planetarium. Each show includes an overview of what is visible in the current night sky and a special focus on some aspect of astronomy.

Reservations are required because the planetarium has limited seating. For contact information, visit the WCU Public Planetarium Shows webpage.