Select Page
Giving Light

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...

read more
Filtered LEDs and Light Pollution

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...

read more
Entraining Circadian Rhythms

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...

read more
Daylight Factors

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...

read more
Controlling Multicolor LED Luminaires

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...

read more
Color Temperature and Outdoor Lighting

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 CCT"...

read more
Climate-Based Daylight Modeling

Climate-Based Daylight Modeling

 Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published:  2016/03/26 daylight, n. The light of day. Apart from having a wonderfully circular definition in most English-language dictionaries, daylight really is just another form...

read more
Botanical Light Pollution

Botanical Light Pollution

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2016/02/17 Blue-rich light from LED streetlights, we are told, is the nemesis of professional and amateur astronomers. Blue light is preferentially scattered by the atmosphere,...

read more
Blue Light Hazards and                                      Television

Blue Light Hazards and Television

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd.  Published: 2017/05/19  If you have grandchildren, you may be old enough to remember “black and white” (that is, monochrome) televisions sets with rabbit ear antennae and some of the...

read more
Blue Light Hazard… Or Not?

Blue Light Hazard… Or Not?

Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd.   Published: 2014/11/05 As a professional lighting designer, you will likely have read about the “blue light hazard” associated with white light-emitting diodes. You will have seen...

read more