This online encyclopedia is a large sample of comprehensive data offering you a possibility to find any information about planetariums. You are given lots of information about space theaters, projection techniques, history, and new developments. Dates of general interest like international conferences and meetings are updated as soon as announced. Our objective is to point out the important role that planetaria play when bringing astronomical knowledge from the scientific frontiers to the public. On these pages you will find inspiration for new projects that may help you to attract visitors and guide them through the fascinating sites of our Universe. If you still miss anything, don't hesitate to contact us.

Have a lot of fun!

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The realisation of the modern planetarium comes in many shapes and sizes, ranging from a small umbrella-like facility of hardly 3 meters to huge domes providing space for several hundred visitors. Such a planetarium may shelter an opto-mechanical star projector (the classical style) as well as a number of video projectors for a digital presentation (virtual style). Difficulties arise when evaluating a planetarium's prominence, especially, when seen through the eyes of the public, who are accustomed to classifying them to "large", "middle", and "small" buildings. A closer look at the parameters, that determine a planetarium, reveals that only two are stable against arbitrariness: the diameter of the dome and the type of the projector. The number of seats, often mentioned in the planetarium's description, turns out to be of little significance.

Details of the Zeiss Mark-VI projector:

  1 - Constellation figures for the Northern hemisphere
  2 - Star globe with 16 Northern star fields
  3 - Mechanical shutter of star field projector (Horizon)
  4 - Milky Way projector (Northern part)
  5 - Planetary cage (Saturn, Sun, Moon)
  6 - Lattice ring for Sun, Moon and vertical circle
  7 - Horizon circle
  8 - Planetary cage (Mercury, Venus, Mars, Jupiter)
  9 - Star globe with 16 Southern star fields
10 - Compass point projector

1612: Galileo Galilei made five attempts to built a machine to reproduce the motions of the Jovian moons. Such a modification of an orrery is called Jovilabium, a combined term from the words for Jupiter and Astrolabe. Galileo's construction was made of cardboard and had no cogs. A version of brass was built after his death and is now in the Museo della Scienza (Museum of the History of Science) in Florence, Italy. Ole Roemer also built a Jovilabium in 1677, and utilised cogs for the first time. It had a crank handle, but the wrong sizes of the objects impeded a useful purpose. Another Jovilabium was developed by Giovanni Domenico Cassini in 1677. It had several disks instead of cogs and was rather a graphical auxillary to predict the positions of the moons as well as their eclipses. The positions were looked up in tables and small balls were shifted along the rings which represented the orbits.

The most successful product of the company RSA Cosmos is the Cosmodyssee meant for small and mobile planetaria. The latest model is number IV and has entered the market in 2007. The mobile version comes in a suitcase and weights 33 kg. Most often it is used in inflatable panetaria. Another version is mounted on a pedestal. This is ideal for fixed domes measuring 3 to 7 m. The height of the main device can be altered from 1,00 to 1,50 m. The control desk is held by a plate at the pillar. 1500 stars are shown by the pinhole projection method, and their brightness can be dimmed continuously. They are accompanied by 12 Messier objects and a slide image of the Milky Way. The planets have to be placed. Their  brightness can be adjusted. Two projectors for the sun indicate its path at winter and summer season, respectively. Four phases of the moon have to be set up manually, and they show surface details. Grids are also available.