The Prague Planetarium has undergone a major modernization that goes far beyond simply replacing the projection equipment. The renovation of this historically protected building, designed by architect Jaroslav Frágner in the 1950s, was no easy task. It was necessary to strip away the layers of modifications accumulated over the past decades, thereby paving the way for the installation of revolutionary LED projection technology.

At the heart of the entire project is a new hemispherical screen from the American company COSM, measuring 22 meters in diameter and boasting an incredible 45 million pixels. No other screen of this size and quality exists anywhere else in the world. Thanks to it, audiences can experience an immersive spatial illusion with extraordinary color depth and realism.

The central Zeiss Jena projector was moved outside the main hall in agreement with heritage preservationists, freeing up space for a new auditorium design. Architects from the collcoll studio designed a tiered geometric layout that visually lifts the audience above the horizon. Capacity has increased by 20% to 277 seats, and the spatial layout facilitates comfortable and safe movement. The seats were custom-designed in collaboration with a Czech manufacturer—they are adjustable, ergonomic, and just comfortable enough to help the audience maintain their focus. Acoustic treatment concealed behind the projection dome further enhances the illusory sensation of infinite space.

The installation of new technology also required new energy and technical infrastructure, which was integrated into the building with the utmost respect for the historically protected structures. The cooling and heat recovery systems were designed with the planetarium’s location in the heart of Stromovka Park in mind—in the summer, heat from the screen is stored in six deep boreholes (each 200 meters deep), and in the winter, it is used to heat the entire building. The dome itself has a thermal output comparable to that of three single-family homes, so we reuse the heat from it within the building.

The renovation also extended to the foyer and back-of-house areas. The original exhibit in the entrance has been replaced by a circular LED screen, which serves as an additional presentation area. The newly designed coat check separates the flow of arriving and departing visitors, enhancing comfort. Over the course of the summer, a new simulator exhibit in the basement will also open, and once the outdoor landscaping is complete, a gift shop will be established near the new exit. An inappropriately placed ramp will be removed from the adjacent rose garden, and barrier-free access through the gift shop will be significantly improved.