Retired star machine celebrated at planetarium


    LOUISVILLE, Ky. – Old technology will be celebrated in a new exhibit at the University of Louisville Gheens Science Hall and Rauch Planetarium.

     An optomechanical star machine that for more than a decade recreated the Earth’s sky on the planetarium’s domed ceiling will be permanently displayed in the lobby.

    The Star Ball was installed in 2001 when the planetarium opened and was replaced in 2013 by a digital projection system, SciDome. The complex Star Ball’s service to planetarium visitors will be recognized Feb. 9 at 7 p.m. at a free, public event.

    “The planetarium’s recently retired optomechanical star machine is an amazing piece of engineering, able to accurately and dynamically represent the entire sky visible from Earth,” said Thomas Tretter, director of the planetarium.

    The Star Ball, state-of-the-art technology in its day, has more than 4,000 tiny holes for light to shine through.

    “This exhibit allows visitors to get a close-up view of the complex and intricate inner workings of the original Star Ball machine.” Tretter said. “During the celebration, we will take visitors into the planetarium dome to show them highlights of what the legacy Star Ball was able to do, such as project the night sky from any location and date on Earth. Then we will demonstrate some of the enhanced features our new digital projection system allows us to do, including a virtual trip through space to the edges of the known universe.”

    The Star Ball will be available for viewing during weekend public shows; the schedule is posted on Additionally, visits to the planetarium can be scheduled for weekdays by calling 502-852-6665 or emailing

    For more information: or Paula McGuffey, 502-852-5855.


    Janet Cappiello covers student success for the Office of Communications and Marketing. She has more than 30 years’ experience in journalism, including working for The Associated Press and magazines such as Vegetarian Times and Sustainability: The Journal of Record. She has been at UofL since 2014.