National Dark-Sky Week
National Dark-Sky Week (NDSW), held during the week of the new moon in April, is a week during which people worldwide turn out their lights in order to observe the beauty of the night sky without light pollution. This event was founded in 2003 by high school student Jennifer Barlow of Midlothian, Virginia and its popularity and participation increases every year. It has been endorsed by the International Dark-Sky Association (IDA), the American Astronomical Society (AAS), the Astronomical League, and Sky & Telescope (S&T).
|National Dark-Sky Week (NDSW)|
|Genre||Astronomy-related events and competitions|
|Frequency||Week of the new moon in April|
The goals of the event are to:
- Temporarily reduce light pollution and raise awareness about its effects on the night sky,
- Encourage the use of better lighting systems that direct light downward instead of into the sky, and
- Promote the study of astronomy.
This event always occurs in April, during the week of the new moon so that the sky can be as dark as possible for optimum viewing conditions.
Jennifer Barlow states, "The night sky is a gift of such tremendous beauty that should not be hidden under a blanket of wasted light. It should be visible so that future generations do not lose touch with the wonder of our universe." Barlow explains, "It is my wish that people see the night sky in all of its glory, without excess light in the sky as our ancestors saw it hundreds of years ago."
Willing participants in this project turn off all unnecessary lighting indoors and outdoors sources in order to reduce light pollution of the night sky.
- Using outdoor light only when needed
- Confine light to specific areas
- Be aware that lights need only be as bright as it is necessary
- Reducing the amount of blue light emissions used
- Use of lighting that faces downward, in order to avoid over illumination, called fully shielded fixtures
Types of light pollution
Light pollution is a broad term used to define excess artificial light that brightens the night sky. Types of light pollution which include:
- Skyglow, a hazy glow produced by the reflection water molecules in the air that encompasses cities which prevent the night sky to be fully seen.
- Light trespass is a condition in which light is oriented into areas in which it is not needed. A common example is street lighting projecting in all directions including the sky which creates a hazy reflection upon the night sky, making it difficult for star observation.
- Over-illumination is the excess supply of light used beyond what is necessary for safety and efficiency.
- Light clutter which refers to the common organizational groupings of lights in cities and roadways.
- Glare is an impeding bright light which cause temporary impairments to human sight. There are three classifications of glare, blinding glare, disability glare and discomfort glare. (See Light pollution)
Implications of light pollution
Light pollution is the adverse effects of artificial light.
By increasing the number of participants, the quality of viewing the sky and stars will be temporarily improved. This is a benefit to astronomers that are faced with light pollution issues such as light trespass and skyglow.
Several animal species have been documented to be affected by light pollution. The glare of street lights cause distraction to nocturnal birds in flight leading to bird crashes into sky scrapers and buildings. The use of light may also cause birds to reproduce or migrate too early. The feeding behavior of insects, bats, sea turtles, fish, replies reflect alterations by artificial light. Sea turtles mistake the glow of electric lights for the shimmer of the ocean, leading them to flock outside of their nest into hazardous areas.
Human circadian rhythm and sleep patterns:
Exposure to light during traditional sleeping hours have are documented to cause disruptions in the circadian rhythm that regulate human sleep cycles. Biologists have noted a decrease in the amount of melatonin, a natural hormone that regulates the Circadian rhythm, in humans that are exposed to light pollution of the night sky. In order to prevent major impact, biologists suggest to increase the amount of natural light exposure during the day and decrease the amount of electrical light consumed at night.
Growth patterns of plants and trees:
Waste of economic resources:
Leaving lights on that are not in use can lead to the waste of economic cost expenditures. Conservation and efficiency is necessary for environmental responsibility. The invention of LED lights, dimmers, motion sensors and times have reduced the amount of energy used.
The best way to take action to promote dark skies is to get involved in local government. There are templates for light ordinances that can legally ban the use of harmful lights and limit commercial lighting to a specific curfew. Currently, there are no nationwide standards regarding light pollution. However, select cities across the United States and Canada are taking initiative to facilitate dark sky cities in order to reduce light pollution and view the night sky within city limits.
|Sr.||Year||Week||New moon (UTC)||Notes||Reference|
|1||2003||1 April 2003|
|2||2004||19 April 2004|
|3||2005||8 April 2005|
|4||2006||27 April 2006|
|5||2007||17 April 2007|
|6||2008||6 April 2008||In 2008, the organizers coordinated the week with Earth Hour.|
|7||2009||April 20–26, 2009||25 April 2009||International Year of Astronomy (IYA 2009)
In 2009, the United States Dark Sky Week becomes International Dark Sky Week
|8||2010||April 4–10, 2010||13–14 April 2010|
|9||2011||3 April 2011||The world's first International Dark Sky City was founded in Flagstaff, AZ|
|10||2012||21 April 2012|
|11||2013||10 April 2013|
|12||2014||April 20–26, 2014||29 April 2014|
|13||2015||April 13–18, 2015||18 April 2015||International Year of Light and Light-based Technologies (IYL 2015)|
|14||2016||April 4-10, 2016||7 April 2016|
|15||2017||April 22-28, 2017||26 April 2017 UTC||The first day (April 22) corresponded with Earth Day.|
|16||2018||16 April 2018|
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