The Bartlett Lighting Simulator at University College London comprises a large geodesic dome covered with 270 individually controlled compact fluorescent lamps that can accurately simulate different sky conditions. Built in 1998, the simulator uses frosted glass diffusers for the sky lamps and a parabolic reflector for the simulated sun. It can achieve calibrated luminance measurements and recreate various photometric parameters and sky profiles to simulate different sky conditions, seasons, and locations of the sun for lighting research and MSc module purposes.

1. Artificial Sky Visit
Contact Peter Raynham (020 3108 9029)
Facility The Bartlett Lighting Simulator
Address University College London, Wates House, 22 Gordon Street, WC1H 0QB.
Tel: 020 7679 4853
Date of visit Thursday 27th October 2011
Purpose of Visit To see the artificial sky and to discuss how it was achieved and how it compares to a
real sky. To enquire about lighting MSc Modules.
Questions Answers
1. Description of the simulator Built in 1998, the artificial sky comprises a large (5.2m diameter)
When was the simulator built? geodesic hemispherical dome, covered with an array of state of the
art light sources and diffusers.
Each of the dome’s 270 energy efficient, compact fluorescent
luminaires are individually controlled in order alter the luminance
distribution; thereby modelling different sky conditions.
2. What lamps are used? The sun is a 50w MR 16 lamp, the sky has 270
 Sky 11w compact fluorescent lamps
 Sun
3. What diffusers are used? The sun is not diffused but uses a 800 mm
 Sky
diameter parabolic reflector.
 Sun The sky luminaires have frosted glass on
them and a black internal baffle to stop back
reflection
4. What Luminance can be achieved?
We tend to consider only the illuminace
 Sky
on the model in the centre and then we are
 Sun
only concerned in relative measurements
5. What is the accuracy of the simulator This depends on what you are trying to
when compared to the real world? simulate, but as are not overly concerned
 Sky with absolute values then most of the
 Sun uncertainties cancel out
6. What photometric parameters were see above
recreated in the simulator and how?

2. Questions Answers
7. What was the original use for the Used with model buildings originally and now
simulator and what is its use now?
8. What modifications have been made New camera integrated into the system
from the original spec?
9. What sky conditions can be simulated? Direct programming supports CIE standard
skys, files for any type of sky may be
imported
10. How is the sky profile programmed? File with a set of luminaire settings
11. How is a sky profile simulated? All sky luminaires individually addressable
(dimmer switches, filters, change
lamps)
12. How is the sky profile defined? see 9
(calculated general skies, real data)
13. If real sky data was used to define the In principle data from IDMP collection
sky profile; how was it collected? stations may be used
14. How do the control systems work and Standard DSI (it was build before DALI)
how do they interface with the
luminaires?

3. Questions Answers
15. How is the Sun simulated? Parabolic mirror
16. How are the Seasons simulated? Sun locations and sky settings
17. What measuring equipment is used and Multi sensor illuminace meter
what is its purpose?
18. Can ‘Just Noticeable Difference’ of I am not sure as I am not exactly sure what
display screens be assessed in the you mean
simulator?
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