Dark Sky Reserves - Blog Posts
It’s international dark sky week! Please enjoy this great Bortle scale.
skyglowproject What sky do you live under? Learn more at SKYGLOWPROJECT.COM
Stargazing is a difficult task, especially under adverse weather conditions, but human beings have also made it much harder for ourselves with all these pesky electrical lights and such. Light pollution affects vast swathes of inhabited land, but the introduction of Dark Sky Reserves helps to improve observational conditions for amateur and professional astronomers. Today, you get to hear more about Dark Sky Reserves as well as the Bortle Scale, which is used to judge the amount of light pollution affecting stargazing within an area.
Below the cut are my sources, music credits, a vocab list, and the transcript of this episode. Suggest what you think I should research next by messaging me here, tweeting at me at @HDandtheVoid, or asking me to my face if you know me. Please subscribe on iTunes, rate it and maybe review it, and tell friends if you think they’d like to hear it!
(My thoughts on the next episode are space race history, the transit of Venus, Shen Kuo, or Walter Baade. The next episode will be up on December 18th.)
Glossary
airglow - a very faint, bluish, naturally occurring glow that hangs around the horizon on Earth, usually within about 15 degrees of the horizon line.
Bortle Scale - an objective scale to measure the clarity and effect of light pollution on a night’s stargazing. Black and grey zones are the best for stargazing, blue is for rural skies, green and yellow are the rural/suburban transition zone, orange is the suburban sky, red is bright suburbia, and white is for cities and inner cities.
deep-sky object - any cosmological object that isn’t individual stars or something from our Solar System. It’s a classification that includes nebulae, galaxies, and star clusters, and it has its roots in amateur astronomy.
ecliptic - the path of the Sun across the sky over the course of a year.
gegenschein - a faint brightening in the night sky directly opposite the Sun. Astronomers think it’s caused by the reflection of sunlight off of dust ejected by comets or resulting from asteroid destruction.
light pollution - the excessive, misdirected, or intrusive use of artificial, human-made lighting. There are several major types of light pollution:
glare - when too-bright and poorly directed lights blind people.
light trespass - when neighboring lights are so bright that their light spills over and illuminates others’ property.
overillumination - when excessive lights are used in a small area.
skyglow - the visible glow caused by light scattering and reflecting off of the droplets of atmospheric molecules.
lumen - a measurement of a light’s brightness.
magnitude - the measurement of a star’s brightness as seen from Earth. The brighter it is, the lower its magnitude value. Ex. the Sun has an apparent magnitude of -27.
Messier object - a deep-sky object included on a list of 103-110 deep-sky objects made by Charles Messier and his colleagues in the 18th century in an attempt to prevent fuzzy, bright objects from being confused with comets.
zodiacal light - a faint brightening in the night sky along the ecliptic that results from sunlight scattered forward off dust in the direction of the Sun.
Transcript
Sources
Sodium lamp light pollution reduction effects via Flagstaff Dark Skies Coalition
Types of light pollution via the British Astronomical Association’s Campaign for Dark Skies, 2009
Light pollution via Sky and Telescope, Dec 2008
The World Atlas of Artificial Night Sky Brightness via the Light Pollution Science and Technology Institute
Lumens and watts via Lowes
UNESCO World Heritage Site list
Invention of the light bulb via SPS Industrial
Lightbulb components via CIO
Walter Baade bio via the Royal Astronomy Society of Canada
International Dark-Sky Association
“An IDA International Dark Sky Reserve is a public or private land possessing an exceptional or distinguished quality of starry nights and nocturnal environment that is specifically protected for its scientific, natural, educational, cultural, heritage and/or public enjoyment. Reserves consist of a core area meeting minimum criteria for sky quality and natural darkness, and a peripheral area that supports dark sky preservation in the core. Reserves are formed through a partnership of multiple land managers who have recognized the value of the natural nighttime environment through regulations and long-term planning.”
“The core area must provide an exceptional dark sky resource, relative to the communities and cities that surround it, where the night sky brightness is routinely equal to or darker than 20 magnitudes per square arc second.”
John Bortle’s article on his magnitude scale via Sky and Telescope, July 2006
“I have created a nine-level scale. It is based on nearly 50 years of observing experience. I hope it will prove both enlightening and useful to observers — though it may stun or even horrify some! Should it come into wide use, it would provide a consistent standard for comparing observations with light pollution.”
John E. Bortle receives the Leslie C. Peltier Award in 2013 via the Astronomical Society
Bortle dark sky scale via Big Sky Astronomy Club
Bortle dark sky scale via LSU
Gegenschein via Sky and Telescope, Oct 2015
Messier List via Fred Espenak’s website, Astropixels
Caldwell List via Students for the Exploration and Development of Space (SEDS)
Intro Music: ‘Better Times Will Come’ by No Luck Club off their album Prosperity
Filler Music: ‘New Son/Burnt Iron’ by Trampled by Turtles off their album Palomino
Outro Music: ‘Fields of Russia’ by Mutefish off their album On Draught