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In the Blood
Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2014/06/25 We most often think of lighting design in terms of lumens, color temperature, and CRI, but there are occasional situations where a deeper analysis is required....
In Search of Luminance
Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2014/11/18 The IES Lighting Handbook, Tenth Edition (IES 2010), describes luminance as "perhaps the most important quantity in lighting design and illuminating engineering." This...
Horticultural Lighting Metrics
Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 08/04/2017 UPDATE 17/08/26 - This article was first published on August 25th, 2017 in Urban Ag News. It was all so easy until recently. Plants require light in order to grow,...
Giving Light
Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2014/05/12 Giving light ... this phrase symbolizes a new philosophy of lighting design, a philosophy in the sense of how we think about the lighting design process. Much like the...
Filtered LEDs and Light Pollution
Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2016/03/03 UPDATE 2016/03/03 - Revised Figure 6. The problem is astronomical -- the blue light emitted by LED roadway luminaires has been shown to contribute to light...
Entraining Circadian Rhythms
Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2015/04/21 There is a fascinating research paper called "Colour as a Signal for Entraining the Mammalian Circadian Clock" that has just been published in the open access...
Daylight Factors
Ian Ashdown, P. Eng., FIES,Senior Scientist, SunTracker Technologies Ltd. Published: 2014/03/05 Nine out of ten daylight simulation programs agree ... and therein lies a story worth retelling. Daylight in History The story begins in the sixth century with the...
Controlling Multicolor LED Luminaires
Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2016/06/11 San Jose, CA, USA: March 31, 2016. LED Engin, Inc. announces the world’s first 7-color, high power LED to be produced on a single emitter. The compact LZ704MU00...
Color Temperature and Outdoor Lighting
Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2015/07/22 UPDATE: Sports field lighting analysis added 15/10/12. [An edited version of this article was published as "STREET LIGHTS: Light pollution depends on the light source...