Did you know that stars are made by hand at Carl Zeiss?

©Anna Schroll

Did you know ...

... that stars are made by hand at Carl Zeiss?


The job of "star-maker" really does exist at the high-tech company. Despite the romantic associations this title evokes, the profession is based on very solid training foundations – for the role of optical technician. But how and why are stars actually made?

The star-maker is employed in the Planetariums division. To clarify a common source of confusion: In a planetarium, visitors may view an artificial night sky, whereas in an observatory, they can observe real celestial objects.

At the heart of a planetarium is a special projector which projects the night sky onto the interior surface of a semi-spherical dome. Walther Bauersfeld presented the first projection planetarium from Carl Zeiss in 1923. Today, the world's largest planetarium – with a dome diameter of 35 meters – is located in Nagoya, Japan.

Regardless of all the technology however, there would be no modern projection planetarium if it weren't for the star-maker's craftsmanship. A planetarium projector from Carl Zeiss is an opto-mechanical system containing either 12 or 32 fixed star projectors, depending on the model. Inside this are round disks with holes designed to recreate an exact and astronomically detailed replica of the night sky. Each hole is illuminated by a single glass fiber. Under a microscope, a total of 9100 glass fibers are individually "threaded" through holes to create 9100 stars – the amount of stars which the human eye can see under optimal viewing conditions. This work requires patience, good nerves and a steady hand. After all, each one of these round disks with a diameter of just five centimeters has to fit up to 900 stars.

Once the threading is complete, the hand-made fixed star projectors are built into and aligned inside the planetarium projector. Millions of planetarium visitors all over the world are amazed by the brilliant and natural-looking night skies on the domes over their heads – unaware that they have the craftsmanship of the star-maker at Carl Zeiss in Jena to thank for the experience!

November 28, 2012