The Downing Planetarium was made possible by the generous donations and support of the late Dr. Harold Downing and his family, Tom and Cynthia Downing. More than 20,000 children from the schools of the Central Valley enjoy the educational shows in the Planetarium and the learning activities in the Downing Museum behind it every year. The Planetarium has a 74-seat star theater with a 30-foot dome.
The planetarium shows are run with a Minolta MS-10 Downing Planetarium star projector and a full dome hemispherical mirror projection system which covers the entire dome with a movie. The full dome system was installed in the summer of 2013. In addition, more than 30 programs are run in the traditional format show library. The traditional format uses 36 slide projectors and a video projector controlled by a single computer running the JHE automation system.