Planetarium as an apparatus
Originally, planetarium is the name of the projection apparatus that was manufactured in the Zeiss Plant in Jena, Germany, in 1923. Unlike the observatory, where a telescope is used to observe real objects in the real sky in place of the observer, planetarium allows for projecting a moving skyline of space on a dome, which only simulates the sky. The viewer thus observes artificial sky and the planetarium’s setting may transfer him to any place on the Earth at any time of day.
This attraction quickly spread throughout the world, so in 1927, there was a planetarium in Vienna, then in Rome, Moscow, New York, etc. In 1956, it was possible to see the first planetarium in Prague in an exhibition of the products of the Carl Zeiss company from Jena. The exhibit was so successful with the visitors, that the Ministry of Culture purchased it and placed it for several months into the vestibule of the Savings Bank at the square Náměstí Míru. After that it was permanently installed in the object of the Observatory and Planetarium in Hradec Králové, where it is still used today.
Planetarium as a building
The need for a special building arose in 1954 after purchasing a greater apparatus (again Carl Zeiss Jena) with a projection dome with a diameter of 23 m. Out of many different options, a location was finally selected on the edge of the Royal Game Preserve, where there used to be a pleasure restaurant with a dance floor and stables for saddle horses. Until the completion of the new building, the apparatus was deposited in the National Technical Museum’s depository.
The house for the planetarium was built according to a project of architect Jaroslav Fragner, which originally only served as a draft. It was greatly modified for the realization, mostly due to the smaller financial budget (stone balustrade is missing, ancient heads of the supporting pillars as well, there were supposed to be 12 statues of working people in the recesses reminding of blank windows, etc.). Unusual orientation of the main entrance into the green of the Stromovka Park reckoned with the creation of a new and wide access road from this direction. Luckily, this also did not happen – as it would mean an extensive clearance of high-grown trees and bushes.
The planetarium was festively opened for public on the 20th November 1960. At that time, it was one of the most technically advanced in the world, and until today it is still one of the largest. Since 1979, it has been a part of the Observatories and Planetarium of the Capital City of Prague (together with Štefánik’s Observatory at Petřín and Ďáblice Observatory).
The apparatus for which the building was built was fully functional until 1988, and after a reconstruction it is still functional today, although it is technically obsolete.
Current technical equipment of the Planetarium
In the early 1990s, a new planetarium from the Zeiss plant took the place of the original apparatus in the astronomical hall, controlled by a computer system named Kosmorama (it contains 230 projectors, 120 projecting bulbs, and they are driven by 16 engines). It can display the sky as it looked at any time in the past and as it will look in the future; it can simulate all types of the eclipse of the Sun and the Moon, it can display the comets, the changing phases of the Moon, etc.
Gradually also the complementary projecting technology changed; there is a new wide-angle, full-sky and panoramic projection and new laser projecting system, and so the cinema hall Starvid allows for watching top quality video projection or the projection of slides on the largest projecting surface in the Czech Republic (843 m2).
In the foyer, there is a permanent exhibition of optics, which is constantly being updated, with a number of interactive exhibits, monitors with up-to-date information on astronomy and cosmonautics, and projections of a small automatic planetarium on a unique vacuum dome.