Kepler 450

KEPLER450 is an Art and Science project to celebrate the history of astronomy in Prague. By projecting the 12 zodiac constellations beneath the impressive concrete infrastructure of the Nusle Bridge, it will create an ephemeral monument to Johannes Kepler's glory on the scale of a cathedral! This project is led by the association Universe-city, in partnership with the architectural firm LOXIA, the town hall of Prague 2 and the French Institute in Prague.

"I see a city whose glory will reach the stars." According to the legend of the founding of Prague, this is what Princess Libuše Premyslides would have said during her prophetic vision at the top of the nearby Vyšehrad hill. The capital of the Kingdom of Bohemia has indeed been linked in its history to the starry sky from its inception. During the heyday of Rudolf II's reign, the emperor brought to his court many intellectuals and artists, such as the Danish astronomer Tycho Brahe. He was the first to map all the constellations, and by observing the 12 signs of the zodiac he created the Emperor's personal horoscope. These astrological tables were continued by Brahe's assistant, Johannes Kepler, who became one of the greatest astronomers in history. By noting there each night the position of the 7 visible planets, he was able to observe cycles which confirmed the heliocentric vision of Copernicus and Galileo, and found the reason why the movement of the planets has a variable speed: the orbits are elliptical and not circulars! This partly explains the phenomenon of the 4 seasons in the Northern Hemisphere. His three mathematical laws on the orbital displacement of the planets were then used by Isaac Newton to calculate the universal constant of gravitation. Kepler also contributed a lot in other fields, such as music with his treatise "Harmonices Mundi", and made a lot of observations in natural science, for example discovering that all snowflakes have hexagonal geometry. Unfortunately, his grave was destroyed during the 30 Years War, which is why a new place should be dedicated to his memory!

This year 2021 is the 450th anniversary of this genius who revolutionized European science. In partnership with the LOXIA architectural agency, our association Universe-city wishes to pay tribute to him with this ambitious project. Opposite the legendary Vyšehrad Hill is the huge Nusle Viaduct, which is a great marvel of engineering and makes travel between central and southern Prague much easier. However, it was built by the Soviet regime, and unfortunately people lost their lives there before security barriers were put up. For the reputation of this place, it is important to transform the valley below which has a lot of potential by making it a more pleasant place for the inhabitants to live. In addition to the new space designed by LOXIA to make the place livelier with new equipment that will create a real meeting place, KEPLER450 will reveal on certain nights… an artificial starry sky! Thanks to two projectors and filters of Gobo technology, we can make the 12 constellations of the zodiac appear above the park of Folimanka, which will evoke the astrological symbols of the clock of Staromeška Náměstí. 

Last summer, we did a test to see how the projectors worked, to see how to correct image distortions. Now, between November 21 and December 21, we will be requesting approximately 100,000 CZK online on, a popular crowdfunding platform. Kepler's real birthday is December 27, 2021, and our dream would be to create the artwork for the first time on this date! Thanks to our partnership with the French Institute in Prague, we will be able to store the projectors in their premises, and we offer the elected representatives of Prague to recreate this work each following year between December 21 and 31, the darkest period of the year, as Kepler scientifically explained. In addition, an ancient tradition associates these first 10 days of Winter with the planet Jupiter...

Benjamin R.

December 3, 2021

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