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Otford Solar System

The Otford Solar System is a scale model of the solar system constructed in and around a small village in south-east England. It is not the largest to-scale representation of the Solar System in the world but it is unique in two respects. First, it accurately depicts the spatial configuration of the planets at a moment in time—midnight on 1 January 2000. Second, it includes four of the nearest stars, to scale and at approximately at the correct distance, in locations around the world. The Otford solar system provides visitors of all ages with an extraordinary insight into the size of the solar system and the larger universe in relation to our small planet.

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Presentation and analysis

Geographical position

Otford is a village in Kent, south-east England. The centre of the model (Sun and inner planets) is situated at the back of the village recreation ground, with the outer planets placed at other locations in and around the village. The nearest star to the Sun, Proxima Centauri, is held in Los Angeles, USA; Barnard’s Star in Port Stanley, Falkland Islands; Sirius in Sydney, Australia; and Ross 154 in Christchurch, New Zealand.

The attractive Kentish village of Otford. Photo:

The attractive Kentish village of Otford. Photo: © Clive Ruggles

Location

  • Sun: latitude 51° 18’ 56.4" N, longitude 0° 11’ 18.0" E
  • Proxima Centauri: latitude 34° 07’ 06.3" N, longitude 118° 18’ 01.4" W
  • Barnard’s Star: latitude 51° 41’ 28.3" S, longitude 57° 51’ 54.6" W
  • Sirius: latitude 33° 51’ 34.6" S, longitude 151° 12’ 16.5" E
  • Ross 154: latitude 43° 31’ 50.7" S, longitude 172° 37’ 37.0" E

General description

At a scale of 1:4,596,000,000, the Sun is a little larger than a football (30.3 cm across). The Earth is the size of a small ball bearing (0.3 cm across) some 32m away. Jupiter, the largest planet, is 162m away and still smaller than a ping-pong ball (3.1 cm across). The Otford Solar System allows a casual visitor to visualise these proportions by physically displaying the Sun and inner planets to scale, on pillars placed around a publicly accessible space—a recreation field. The model not only extends to the outer planets, scattered in and around the village, but also to four of the nearest stars, displayed to scale in museums around the world.

Although larger scaled representations exist of the solar system itself, the inclusion of the four nearby stars creates a far larger scale model, one that extends across the planet. In that sense the Otford Solar System is rightly claimed to be “the largest scale model in the world”.

The Sun, the centrepiece of the Otford solar syste

The Sun, the centrepiece of the Otford solar system model, reflecting the light of the real Sun. Photo: © Clive Ruggles

Brief inventory

The Sun on its pillar with the Earth pillar behind

The Sun on its pillar with the Earth pillar behind. Photo: © Clive Ruggles

The centrepiece of the Otford Solar System is a reflective blue dome, the upper part of a sphere 30.3 cm in diameter, set into the top of a concrete pillar. This dome, and the imagined sphere, represents the Sun. Engravings on the top of the pillar indicate the directions of the planets.

 

Each planet is represented by a to-scale engraving on a flat disc mounted on its own pillar. Each of these discs is 30.3 cm in diameter, so as to give an idea of the size of the planet concerned in relation to that of the Sun. The Earth’s pillar includes the Moon and Jupiter’s includes its satellites Io and Europa.

Earth to scale on its pillar. Photo: © Clive Rugg

Earth to scale on its pillar. Photo: © Clive Ruggles

Jupiter to scale on its pillar. Photo: © Clive Ru

Jupiter to scale on its pillar. Photo: © Clive Ruggles

 

The Otford inner solar system with Mars in the for

The Otford inner solar system with Mars in the foreground. The distant pillars, left to right, are: Mercury, Venus, the Sun, and Earth. Photo: © Clive Ruggles

Mars is the only planet not placed on a pillar: this is for practical reasons, as it is located between two football pitches. Instead, the Mars disc is set directly into the ground.

 

The outer planets can be found in various locations in and around the village:

Jupiter

Jupiter

Saturn

Saturn

Uranus

Uranus

Neptune. Photos: © Clive Ruggles

Neptune. Photos: © Clive Ruggles

 

Pluto. Photo: © Clive Ruggles

Pluto. Photo: © Clive Ruggles

The Otford Solar System having been constructed prior to 2006, Pluto is included as a planet. Its pillar is in an isolated location outside the village reached by rural footpaths, just under 1 km in a direct line from the Sun pillar.

 

The four nearby stars are placed in supervised locations (observatories and museums) at distances that differ by no more than 5% from the "true" distance to scale (measured around the globe on a great circle).

Proxima Centauri forms part of a permanent exhibit in the Griffith Observatory, Los Angeles.

Proxima Centauri, the nearest star beyond the Sun,

Proxima Centauri, the nearest star beyond the Sun, displayed in the Griffith Observatory, Los Angeles. Close up (left/top) and in context (right/bottom). Photos: © Edwin C. Krupp

 

Barnard’s Star is in the Stanley Museum, Port Stanley, Falkland Islands; Sirius is in Sydney Observatory, Sydney, Australia; and Ross 154 is in Christchurch Museum, Christchurch, New Zealand.

History

Map in the heritage centre tracking the current po

Map in the heritage centre tracking the current positions of the outer planets. Photo: © Clive Ruggles

The initial idea for the Otford Solar System was conceived by David P. Thomas, who carried out the design, surveying and calculations jointly with councillor B.J. Keenan.

The Otford Solar System was set up as a millennium project by Otford Parish Council. For this reason, it was spatially configured so as to accurately reflect the positions of the planets at midnight on 1 Jan 2000. The positions of Juiter, Saturn and Pluto were slightly adjusted in order to make them accessible.

A chart in the village museum and heritage centre keeps track of the changing positions of the planets through the local landscape over time.

Management and use

Present use

The model itself is owned by Otford Parish Council and was built using the most durable materials that could be obtained within the available budget.

The Sun and all the planets are in openly accessible locations. Visitors are encouraged to visit every planet in the solar system, which at a leisurely walk (“at about twenty times the speed of light”) is estimated to take somewhat under two hours.

The distant stars are situated in observatories and museums and may be subject to viewing restrictions.

State of conservation

Close-up of the Mars plate, showing its state of r

Close-up of the Mars plate, showing its state of repair in October 2018. Photo: © Clive Ruggles

During the almost two decades since the model was first constructed, the Sun dome and the engraved plates for the planets have sustained numerous small scratches and dents but the markings themselves are still clear.

The Mars plate, being flat on the ground, is more extensively scratched and scraped than the others.

Pluto, situated at the side of a footpath about 1 km outside the village, was found in an overgrown state in October 2018 (see picture above).

 

Sirius, photographed on top of a cupboard in Sydne

Sirius, photographed on top of a cupboard in Sydney Observatory in November 2018. Photo: © Toner Stevenson

Of the four nearest stars, only Proxima Centauri is known to be on permanent display. Sirius is preserved in Sydney Observatory, but in November 2018 was being stored, unlabelled, on top of a cupboard. As of February 2019, we have been unable to establish the current status of Barnard’s Star in the Falkland Islands or Ross 154 in New Zealand.

Main threats or potential threats

The Sun and planets are in open places and subject to gradual deteoration from weather and human interference. They could also be subject to vandalism.

The four nearby stars are under cover and should be safe from damage but could be forgotten and lost.

Protection

The components of the model in and around Otford are in public places and unprotected. The four nearby stars, on the other hand, are in managed locations.

Bibliography (books and published articles)

Otford Solar System, leaflet produced by Otford Parish Council Millennium Project, 2000. Available from Otford Heritage Centre, 21 High Street, Otford, Kent, TN14 5PG, UK (+44 1959 524808)

Links to external sites

Back to the Astronomical Heritage - Places connected to the Sky

Return to the Places connected to the Sky map/list page.

about the author(s)

Clive Ruggles lives in Leicester (United Kingdom)

 
 


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