Armagh’s Human Orrery Reproduced Internationally

The Armagh Human Orrery is the first large-scale outdoor exhibit to show with precision on the ground the positions of the main planets, a dwarf planet and two comets. It is an innovative education and learning tool designed to explain the motion of the planets around the Sun and the changing position of Earth, relative to those planets, as it too revolves around the Sun. Launched at the Observatory almost nine years ago, the model is fun to use, entertaining and participative. The model has now been reproduced at a number of locations, notably at the King’s School, Peterborough, and at Christ the Redeemer Primary School, Belfast, and most recently at the Eureka High School, Nepaltar, Kathmandu, Nepal.

Human Orreries are being used in different forms and at different locations right around the world. Those based on the Armagh model highlight an important recent contribution of astronomers at Armagh to the development of new astronomy education resources worldwide, in part through its involvement with the European Universe Awareness programme, EU-UNAWE, a programme funded through the European Community’s Seventh Framework Programme (FP7/2007–2013) under grant agreement No. 263325. They also illustrate how, with the support of the Northern Ireland Department of Culture, Arts and Leisure, astronomers at Armagh are helping to put Northern Ireland and the City of Armagh at the centre of creativity worldwide.

The idea behind the Human Orrery, a concept that goes back many years, is to provide a large-scale interactive educational facility that promotes greater understanding of astronomy, mathematics and space science, and Universe Awareness. People can pretend they are the planets or other solar-system bodies, and learn through their active involvement in the model about the different orbits and the orbital periods of each object around the Sun. The Human Orrery is also an accurate map showing the relative distances between each object and their respective directions in space relative to the Sun, for example as seen from the Earth, or from any other vantage point in the solar system. This is a great way to get an understanding of the relationships between these solar-system objects and of Earth’s place in space.

In the Armagh Human Orrery, the positions of the planets and other solar-system objects are marked on the ground at 16-day time intervals, a literal time "step" on the ground chosen to ensure the clockwork precision of the model for many years either side of the present day. Beyond the most distant planets easily visible with the naked eye, namely Jupiter and Saturn, are the thirteen zodiacal constellations through which the Sun appears to pass in the course of a year, and pointers to more distant and exotic objects in the Universe, such as bright stars many hundreds of light years away, and galaxies and quasars at much greater distances.

FOR FURTHER INFORMATION PLEASE CONTACT: Mark Bailey at the Armagh Observatory, College Hill, Armagh, BT61 9DG. Tel.: 028-3752-2928; FAX: 028-3752-7174; mebat


  1. For full details of the Armagh Human Orrery, see
  2. For a summary review of the Human Orrery and the background to the model, see: PDF file.
  3. For an example of a novel portable human orrery, see: PDF file.
  4. For images of various Human Orreries, see this link. Here there are the following images:
    1. The Armagh Human Orrery
    2. The Human Orrery at the King’s School, Peterborough
    3. The Human Orrery at Christ the Redeemer Primary School, Belfast (2 images)
    4. The Human Orrery at the Eureka High School, Nepaltar, Kathmandu, Nepal (2 images)

Last Revised: 2013 October 25th