Celestial globe

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Celestial globe by Johannes Praetorius , 1566

A celestial globe (lat. Globus coelestis) is the representation of the starry sky on an apparent celestial sphere . It shows the position of the fixed stars and the constellations in an undistorted, but mirror-image position, because the observer is looking at the globe from the outside . With celestial globes, the sky is shown from the outside on the sphere. The observer has to "put himself in the place of the globe" in order to see the sky properly.

Two advantages of the celestial globes were decisive for their earlier meaning:

  1. freedom from any kind of distortion if the globe is made precisely enough
  2. the quick and safe usability as an analog computing device , especially if a terrestrial globe with the same diameter was present.

history

The earth and celestial globes appeared in antiquity - Claudius Ptolemy wrote z. B. Instructions. At the end of the 10th century, Gerbert von Aurillac wrote a letter describing the manufacture of a celestial globe. In the late Middle Ages to Globes prevailed widely. Later, attention was also paid to their artistic execution, and numerous court astronomers carried out special designs for their clients. Some of them are equipped with a drive in the form of a tellurium , e.g. B. a very precisely made double copy by Peter Anich from the 18th century. One of the first famous specimens from the time of discovery was completed by Martin Behaim in 1492 - based on a map of the world by Paolo Toscanelli . The combination of terrestrial and celestial globes is unique in the St. Gallen globe from the 16th century , which is now in the Swiss National Museum . The Austrian National Library has one of the largest globe collections in Europe ; other collections can be found at many large museums and also in private ownership.

Types

In addition to globes of the starry sky and earth , there are also globes of the moon , Mars and Venus .

The Gottorf giant globe is a hollow globe and represents the globe on the outside, inside it hides a planetarium that shows the starry sky and the course of the sun including its movements as they can be seen from the earth.

Web links

Commons : celestial globe  - collection of images, videos and audio files

Individual evidence

  1. ↑ Nikolaj Michajlovic Bubnov (ed.): Gerberti postea Silvestri II papae Opera Mathematica "(972-1003)". R. Friedländer & Sohn, Berlin 1899, ep. 148 (2nd reprint. Olms, Hildesheim et al. 2005, ISBN 3-487-00422-4 ).