NIGHT SKY AND DARK ENVIRONMENTS: BEST MANAGEMENT PRACTICES FOR ARTIFICIAL LIGHT AT NIGHT ON BLM-MANAGED LANDS TECHNICAL NOTE 457 73 mesopic vision: a combination of photopic vision and scotopic vision activated in low but not quite dark lighting situations and characterized by poor visual acuity and color discrimination. Most nighttime outdoor and traffic lighting scenarios are in the mesopic range. See photopic vision, scotopic vision, and visual acuity. Model Lighting Ordinance (MLO): the “Joint IDAIES Model Lighting Ordinance” is a publication designed to help municipalities develop outdoor lighting standards that reduce light pollution. The MLO uses lighting zones to classify land use with appropriate lighting levels, limits the amount of light used for each zone, and uses the IES TM-15-20 BUG (backlight, uplight, and glare) classification. See BUG rating system. M/P ratio: see melanopic/photopic ratio. national conservation area: an area that is part of the National Conservation Lands that is managed to conserve, protect, and restore the exceptional scientific, recreational, cultural, historical, and ecological values for which it was designated. National Conservation Lands: an organized system of public lands managed by the Bureau of Land Management that have received special designation for their scientific, cultural, educational, ecological, and other values. This system was formally established as the National Landscape Conservation System by Title II of the Omnibus Public Land Management Act of 2009 and includes national monuments, national conservation areas, wilderness areas, wilderness study areas, national wild and scenic rivers, national scenic and historic trails, and other units. national historic trail: a trail that is part of the National Conservation Lands. These trails follow, as closely as possible, the original trails or routes of travel of national historic significance and are managed to preserve the remnants of nationally significant pathways and the settings in which they are located. national monument: an area that is part of the National Conservation Lands that is designated to protect objects of scientific and historic interest by proclamation of the President under the Antiquities Act of 1906 or by Congress through legislation. Designation provides for the management of these features and values. national scenic trail: a trail that is part of the National Conservation Lands. These trails are established by an act of Congress and are intended to provide for maximum outdoor recreation potential and for the conservation and enjoyment of nationally significant scenic, historical, natural, and cultural qualities of the areas through which these trails pass. National scenic trails may be located to represent desert, marsh, grassland, mountain, canyon, river, forest, and other areas, as well as landforms that exhibit significant characteristics of the physiographic regions of the nation. natural darkness: the illuminance experienced in the absence of outdoor artificial light at night. natural lighting: natural lighting is light that arises from natural sources (i.e., light that occurs in the natural environment without action by humans). There are many types of natural lighting, including, but not limited to, sunlight, moonlight, starlight, and light from other celestial objects, and also lightning, fire, and bioluminescence. niche partitioning: the process by which competing species use the environment differently in a way that helps them coexist. See temporal niche partitioning. night sky impact: an interference with enjoyment of dark night skies or an effect on wildlife resulting from light pollution. nocturnal: done, occurring, or active at night. over-illumination (also over illumination): the use of lighting intensity higher than that which is appropriate for a specific activity.
RkJQdWJsaXNoZXIy NTkzMzk=