Launch Of Human Orrey

The Armagh Observatory’s ‘Human Orrery’ is the first large outdoor exhibit in the world to show accurately the elliptical orbits and changing relative positions of the planets and other solar system bodies with time. It has been constructed with the support of the Northern Ireland Department of Culture, Arts and Leisure (DCAL) and is the first major addition to the Observatory Grounds and Astropark for more than a decade. A ceremony to mark its construction will take place at the Observatory on the morning of Friday 26th November.

An orrery is a dynamic model of the solar system, designed to show the positions, relative orbits and distances of the planets about the Sun. It shows the orbital periods of objects revolving around the Sun and can be used to illustrate a wide range of celestial phenomena, including planetary alignments, conjunctions, transits, and the laws of orbital mechanics.

The name ‘Orrery’ for the first orrery, which was invented 300 years ago by the English clockmaker and inventor George Graham (c.1674–1751), was popularized by the Irish essayist Sir Richard Steele (1672–1729), in honour of Charles Boyle (1674–1731), the fourth Earl of Orrery. The name has since been attached to any device designed to show the planetary motions.

In the Human Orrery, people play the role of the moving planets and other solar system bodies. The model provides an accurate map of the orbits of the six naked-eye planets, an asteroid and two comets, and shows their positions at any time. When the exhibit is finally completed, it will also show the thirteen zodiacal constellations through which the Sun passes in the course of a year and the directions to a wide range of more distant objects in the Universe.

Mark Bailey, the Observatory Director, said: “The Human Orrery is great way to explain the Earth’s position in space. You can look at the positions of the Sun, planets and other objects on the ground and immediately work out which objects are visible tonight, or at any other time, and where they will appear in the sky relative to one another.”

The Human Orrery is also great fun to use. It provides a wealth of fascinating educational opportunities to engage people not just in science and mathematics, but also in the art of learning how to observe and take careful measurements, and so how to discover new things about the world in which we live.

The ‘inspiration’ of astronomy extends well beyond pure and applied science and technology, and the launch of the Human Orrery is therefore also an opportunity to highlight the breadth of cultural activities supported by the DCAL as well as astronomical research. In particular, the Launch will include the performance of an innovative ‘Dance of the Planets’ performed by children from the local Armstrong Primary School.

The Opening Ceremony will begin at 11:45 in the Observatory library, and will include formal contributions on behalf of the Observatory, the DCAL and the Particle Physics and Astronomy Research Council (PPARC). Many of those who have contributed to the creation of this world ‘first’ for Armagh will be present, as too will other invited guests and some of the Observatory’s staff, students and senior management.