Events of Interest at STEM Laboratory
| 2016 | ||
| List of events: | ||
| Date | Location | Description |
| June 12-16, 2016 | Hilton San Diego Bayfront San Diego, CA |
“Artificial Lighting Protection of Mauna Kea Observatories: An Experiment to Replace LPS Street Lighting With LEDs in Waikoloa Village, HI” Presented by Dr. Eric R. Craine at: 228th Meeting of American Astronomical Association.  [Abstract] Segments of the astronomical community have long lobbied in support of the use of Low Pressure Sodium (LPS) street lights as a method of minimizing impacts of sky glow on neighboring observatories. There has been vociferous objection to the replacement of LPS by Light Emitting Diode (LED) street lights. Such replacement is being precipitated by advances in lighting technologies, high economic efficiencies of LEDs, and plummeting interest in manufacturing LPS fixtures. Waikoloa Village, HI, located on the western slopes of Mauna Kea, home to major northern hemisphere observatories, has for many years been almost exclusively illuminated by LPS lighting. During the winter of 2015-2016 the County of Hawaii Department of Public Works, Traffic Division replaced the approximately 550 LPS street lights in the community with Filtered LED (FLED) fixtures on a one-for-one basis. About 100 other LPS lights on private properties in the community were similarly replaced by the lighting manufacturer. This retrofit offered an excellent opportunity to make measurements of lighting parameters in the community before and after the retrofit process. Measurements were made using satellite, airborne, and ground based observations, and included photometric, photographic, and spectroscopic measurements. Data analyzed included integrated brightness of the community, zenith angle function brightness distributions, and spectral energy distributions. We present the results of these observations and discuss their implications for future protection of astronomical observatory sites. |
| June 12-16, 2016 | Hilton San Diego Bayfront San Diego, CA |
“An Approach to Objectively Defining and Ranking Dark Night Communities” Presented by Dr. Roger B. Culver at: 228th Meeting of American Astronomical Association. [Abstract] There has long been an interest in protecting dark skies around astronomical observatory sites, a task that has become more urgent with the rapid growth of communities surrounding many of these locations. "Dark sky communities" have been discussed in the context of stimulating interest in mediating effects of artificial light at night, and efforts have been made in some areas to attempt to legislate less intrusive lights. Arguably, the latter has been largely unsuccessful, and the former represents a very small percentage of the extant dark night areas. In nearly all instances, the trend is for community contributions to the overall light at night output to increase with time. A complementary, if not alternative, approach is to recognize that all communities are "dark night communities" until they are not. This implies, of course, an understanding of quantitative levels of light output and distributions, and some agreement on thresholds beyond which a community ceases to satisfy definition as a Dark Night Community. Three parameters of primary interest in this regard are 1) integrated community brightness as seen from the zenith, 2) zenith angle brightness distribution, and 3) spectral energy distribution. The first we have addressed using Suomi VIIRS satellite data, which we discuss in this presentation. These data can be further parsed by comparing with demographic databases of interest, such as population and area. In this presentation we discuss the metrics involved, a formula for weighting the metrics to generate a comparative score, and the implications of each for the evaluation of energy waste in hundreds of communities that have now been ranked. |
| June 16-18, 2016 | Ontario Airport Hotel Ontario, CA |
“Empirical Measurements of Filtered Light Emitting Diode (FLED) Replacements of Low Pressure Sodium (LPS) Street Lights at the Base of Mauna Kea, Hawaii” Presented by Dr. Eric R. Craine at: Symposium on Telescope Science SAS Symposium [Abstract] Low pressure sodium (LPS) public lighting, long favored by astronomers and dark sky advocates, is in decline due to a variety of economic issues. Light emitting diode (LED) technology is a rapidly ascendant mode of lighting in everything from residential to commercial applications. The resulting transition from LPS to LED has been accompanied by great angst in the environmental community, but very little has been done in the way of empirical measurement of LEDs in the field and their actual impacts on communities. The community of Waikoloa Village, Hawaii is located on the western slopes of Mauna Kea, within direct line of sight view of the major astronomical observatories on the mountain summit. Waikoloa has been rigorously illuminated almost exclusively by LPS for many years in acknowledgement of the importance of the Mauna Kea Observatories to the Big Island of Hawaii. As LPS ceases to be a viable alternative for local government support, a decision has been made to experimentally retrofit all of the Waikoloa street lighting with filtered light emitting diode (FLED) fixtures. This action has rendered Waikoloa Village a unique laboratory for evaluating the effects of such a change. STEM Laboratory has been awarded a research grant to make a variety of measurements of the light at night environment of Waikoloa Village both before and after the street light retrofit program. Measurements were conducted using a combination of techniques: Satellite Data Surveys (SDS), Ground Static Surveys (GSS photometry), Ground Mobile Surveys (GMS photometry), Airborne Surveys (ABS photography), and Spectroscopic Surveys (SpecS). The impact of the changes in lighting sources was profound, and the preliminary results of this extensive program are discussed in this presentation. |