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Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2015/07/20 "Oh, East is East, and West is West, and never the twain shall meet." When Rudyard Kipling wrote this line in his poem The Ballad of East and West (Kipling 1892),...
Ian Ashdowna, Chris Jacksonb, Joel Spahnc, Todd Saemischd a. SunTracker Technologies Ltd., Victoria, Canada. b. Lighting Analysts Ltd., London, UK. c, d. Lighting Analysts Inc., Littleton, CO. Published: 2017/02/11 (Updated 2021/04/12) Ceriss365 and DAYSIM are...
Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2015/11/24 A previous blog article -- The Kruithof Curve -- examined the history of the Kruithof curve (Kruithof 1941]) shown in FIG. 1: FIG. 1 – Kruithof curve, modern version...
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. One...
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 is...
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, and...
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...
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...
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...
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...