"The sky, our common and universal heritage, is an integral part of the environment perceived by humanity. Humankind has always observed the sky either to interpret it or to understand the physical laws that govern the universe. This interest in astronomy has had profound implications for science, philosophy, religion, culture and our general conception of the universe". Proclamation of 2009 as International Year of Astronomy. UNESCO General Conference. Paris 2005.
“Persons belonging to future generations have the right to an uncontaminated and undamaged Earth, including pure skies; they are entitled to its enjoyment as the ground of human history of culture and social bonds that make each generation and individual a member of one human family.”
Universal Declaration of Human Rights for Future Generations. La Laguna,
1994. Website: STARLIGHT:
International Initiative in Defence of the Quality of the Night Sky as
Mankind’s Scientific, Cultural and Environmental Righs
0. Compilation of regional night sky photometry HERE
1. Denver City and County studying new lighting regs... details available at website DENVERGOV.ORG and search on Lighting Regulations
2. Useful links to Colorado city, county, state lighting regs:
Colorado IESNA and select link to LIGHTING CODES, near end of left column.
Light TRESPASS and GLARE refer to unwanted and harmful lighting.
During 2001, the Colorado Legislature agreed and modified state law to address these issues: SECTION 2, ARTICLE 82 OF TITLE 24, COLORADO REVISED STATUES IS AMENDED BY THE ADDITION OF A NEW PART TO READ: PART 9, OUTDOOR LIGHTING FIXTURES.
Astronomers are NOT AGAINST SAFETY, but are very worried about destruction of the night sky by lighting that shines uselessly into the sky, wasting money and depriving everyone of their cosmic birthright, not to mention causing inferior sleep and melatonin disruption. Badly aimed light also produces trespass nuisance, and disabling glare -- especially for older people.
The simplest solution also saves money: add a shield on top of new lighting, to direct all of the light toward the ground where it is needed.
Also, the use of motion sensors and timers reduce the cost of lighting to only when it is really needed.
GLARE: The 8th edition of the IESNA Lighting Handbook (1993) defines glare as the sensation produced by luminance within the visual field that is sufficiently greater than the luminance to which the eyes are adapted to cause annoyance, discomfort or loss of visual performance and visibility. It stands to reason, then, that any good outdoor lighting design will minimize glare. If the light source itself is more apparent than what it is illuminating, then you have bad lighting.
Light TRESPASS is light that is distributed where it is not wanted or needed. Streetlighting, for example, should light streets and sidewalks, not shine into second floor bedroom windows or illuminate rooftops. Also known as spill light, light trespass occurs whenever light shines beyond the intended target and onto adjacent properties.
UPLIGHT is, in the truest sense of the word, wasted light. Light that goes directly up into the night sky is "lost in space" and serves no useful purpose. Uplight is the bane of astronomers and the occasional stargazer because atmospheric scattering artificially brightens the night sky, making distant celestial light sources difficult or impossible to see. Uplight often results from light fixtures which also produce glare and light trespass.
And from NEMA: FULL CUTOFF fixtures are those that allow "no light at or above a horizontal plane located at the bottom of the luminaire" (lamp plus fixture).