Machina Planetarum Roemeri

The Huge Orrery  In February 1991 a reconstruction of an almost 300 years old orrery was installed in Copenhagen. This planetary machine was originally a prototype invented by Ole Rømer in Paris 1677 and installed in the Roundtower Observatory in Copenhagen in 1697.  In honour of  the  great astronomer Tycho Brahe, it showed the Tychonic concept of the universe, with the Earth in centre of our solar system, the Sun moving round the Earth, and the planets round the Sun.  In the year 1717 Peder Horrebow altered this machine from showing the Tychonic concept to a machine showing the Copernican concept as well. With a small device he could change the machine between the two systems.	The handcoloured starmap with the gear, invented by Roemer in 1677.
The orrery can be seen at the Tycho Brahe Planetarium in Copenhagen.	This famous orrery was the first  public planetarium. Unfortunately  it was severely damaged during the fire of Copenhagen in 1728.  The reconstructed planetarium,  named Machina Planetarum Roemeri,  is now installed in the Tycho Brahe Planetarium of Copenhagen.  This planetarium opened in  February 1991, and up to now  more than 3 million people have already seen and used the machine. School children have become familiar with the sky and the planets as well as with the history of observing our part of the Universe.
The planetarium is hanging from the upper ceiling. Its background is a constellation map. It has additional wheels for indicating the year, the month and the day and can be operated by turning a crank-handle.  A fragment of the constellation map, the remains of the transmission, and an original copperplate by Horrebow showing the machine, made it possible to produce this authentic and beautiful planetary machine.  It has a diameter of 3640 millimetres and a weight  of about 325 kilos.	The Counter with the handcrank showing days, weeks and years.

References:
Poul  Darnell: The Planetary Machines at Rosenborg. Article in ISBN 57-872-0053-8.
Henry C. King: Geared to the Stars. University of Toronto Press. Toronto 1978.P.109
Rhodos: Dansk  Astronomi gennem 400 år. Red.: Claus Thykier Copenhagen 1190.
ISBN 87 7245 81 1