Technical Report: The Mathematics of Orbital Solar Reflectors
Technical Report: The Mathematics of Orbital Solar Reflectors I. Executive Summary At the time of their original submission to the FCC for launch approval, Reflect Orbital claimed they would be able to deliver illuminances up to 5x that of a full moon (1.6 lux). A...
Rethinking the Photometric Data File Format
Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2017/03/01 If you perform lighting design calculations today, you can thank the efforts of the IES Computer Committee (IESCC) some thirty years ago. Its members recognized...
Phytochrome and PSS
Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2016/12/09 Horticultural lighting is currently one of the fastest-expanding markets in commercial lighting, with projected revenues of several billion dollars in less than...
Photometry and Photosynthesis
Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2014/12/10 UPDATE 15/04/13 -- This article was first published on December 10, 2014. A revised version was published as "LED Lighting for Horticulture" in the Mar/Apr 2015...
Mobile Light Pollution
Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2016/01/21 At first glance, this appears to be an innocuous question: How much light pollution is attributable to automotive headlights? It is also a good question in that...
Mesopic Photometry and Statistics
Ian Ashdown, P. Eng., FIES, Senior Scientist, SunTracker Technologies Ltd. Published: 2014/04/21 One of the joys of statistics is that you can never be proven wrong ... In a previous All Things Lighting article titled "Understanding Mesopic Photometry"...
Light Pollution and Uplight Ratings
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...
Cerise365 and DAYSIM
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...
Kruithof Revisited
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...
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....