Mirror-Box Artificial Sky

A low cost installation for teaching and professional use

The Artificial Sky is of the mirror-box type as described by Hopkinson and orginally developed at the BRE. The Artificial Sky has a brightness distribution that closely approximates to the CIE Standard Overcast Sky*. This particular design has been developed at the Martin Centre, Cambridge University, for its low cost and simple installation. It provides a way of testing scale models, usually between 1:20 and 1:100 scale, both quantitatively i.e. by Daylight Factor distribution, and qualitatively by direct observation and photography, under realistic lighting conditions.

Fitted with 'de luxe daylight' lamps (5400° K), the Artificial Sky provides an illuminance in excess of 3500 lux and good colour rendering for photography. With an electrical load of just 576W and by using electronic ballasts, the need for mechanical cooling of the light sources is avoided. The lamp fittings are attached to an opaque lid that enables the Artificial Sky to be sited without the need to alter existing artificial lighting arrangements.

The Artificial Sky is delivered to the site in knock-down form, allowing access to its final location through doors and stairways etc. It is then assembled, usually in one day, and handed over ready for use. The Artificial Sky is free standing and the lighting can be powered from one 13 amp socket.

This photograph shows the interior of the
Artificial Sky.
A photograph of
the exterior of the Artificial Sky.

The internal dimensions are 2400mm square, 2050mm headroom, allowing comfortable room for professional testing of large models, or demonstration to several students. The overall size is 2600mm square, 2500mm high, requiring floor to ceiling height of approximately 3000mm. (2700mm minimum).

A working table of 950mm height, measuring 1100mm, is provided. This surface is large enough to provide support for model obstructions and realistic ground surfaces.


Customers who have bought the mirror-box Artificial Sky include:

  • Martin Centre, Cambridge University
  • Southbank University
  • University of North London (London Met)
  • University of Central England (Birmingham City University)
  • University of Westminster
  • University of Brighton
  • Sheffield University
  • Sheffield Hallam University
  • University of Nottingham
  • Centre for Advanced Technology
  • Canterbury School of Architecture
  • Kingston University

Please contact us for current price of the Artificial Sky, including work table, assembly and delivery costs.


A full set of detailed working drawings can be purchased for £600. The package includes notes on manufacture and assembly, and support with any questions that may arise.


*Commission Internationale de l'Eclairage - the International Commission on Illumination