1937: The first projector not manufactured by Zeiss was constructed by the brothers Frank and John Korkosz in Springfield, Massachusetts. It was a sphere of 1 meter and displayed 7150 stars down the the 5th magnitude but no planets. The star fields were arranged on 41 individual plates. The projector went into service on October 10th, 1937. It exhibits an incredible robustness and is one of the oldest still operating machines in the world. While John handled the technical details about the instrument, Frank devoted himself to the public presentations. In the course of the following two decades he conducted more than 10,000 shows and gained a widely known reputation. His brilliant star demonstrations reached nearly 1 million people. In 1958, Frank became director of the Springfield Museum of Natural History.

In the late 1950ies Frank and John built a second and larger projector for the Hayden Planetarium in Boston, MA. It used separate lamps for each of the different magnitude stars. Its service started in 1958. The lacking of spare parts as well as planet projectors gave rise to the decision of a replacement. In the mid 1970ies, a new Zeiss projector was installed.