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International Dark Sky Week

Spring is finally in full swing and if you’re like me observing season is about to kick off again.  I hate observing in the cold so when April rolls around it’s usually an indicator that better nights are coming…unless you live on the East Coast where it’s been unseasonably cold and cloudy for the last month.  April is also exciting because it is Global Astronomy Month.  Each year since 2009 Astronomer Without Borders has designated April as Global Astronomy Month to raise awareness for the study of astronomy both professionally and amateur.  In my opinion, the biggest part of GAM is International Dark Sky Week.  Beginning tomorrow April 5 and continuing through April 11, Astronomers Without Borders and the International Dark Sky Association are teaming up to raise awareness of the issue of light pollution.  If you’ve read this blog before you’re probably familiar with the light pollution as I write about it quite frequently.

Because of light pollution, the artificial brightening of the night sky, less than a third of Earth’s population lives under natural, starry skies.  Fifty percent of Americans and 75% of Europeans have to travel at least an hour from their homes to see a natural star-filled sky unaffected by light pollution.  From my home in Maryland I have to travel 4.5 hours to reach the only truly dark sky spot around, Cherry Springs State Park in Potter County, Pennsylvania.    I am willing to make this pilgrimage once or twice a year but there should be somewhere closer to observe from that has a quality dark sky.  The reality is, however, that these places are slowly dwindling in number.  Artificial light, the scourge of the night sky, is slowly but surely conquering the beauty of the natural night sky.

Light pollution comes from poorly designed artificial light sources we use at night.  Most of these light sources are from street lights that are unshielded so that light escapes upwards into the air which causes the light particles to scatter and create that familiar sky glow effect.  Other problems are that we often use wattage that is too high for the task we’re trying to accomplish.  If you’re using too bright of a light the light actually reflects off the ground and bounces back up into the sky to contribute to the sky glow.

NYC sky glow creates an ugly orange blanket over the city

NYC sky glow creates an ugly orange blanket over the city

You’ve also probably noticed the annoying glare that unshielded lights cause while driving.  Glare comes from the bright ball of light generated by a typical drop lens or acorn style street light.  See the example below for a typical “glare bomb”.  The glare created by these lights can not only be annoying while driving, they can also be dangerous for people with poorer eyesight such as seniors or people with sight disorders.  They are also so bright that they can mask important things like road signs and signals along with pedestrians and animals in the road.

Example of "glare bomb" acorn lights  Source: Creation Photography

Example of “glare bomb” acorn lights Source: Creation Photography

Light trespass is also an result of poor lighting design.  Light trespass occurs when a light from a neighbor or nearby building shines, or trespasses, on your property.  For example, a stray light that shines into your bedroom at night that causes you to get inadequate sleep.  To make a long story short, the lighting used should fit the requirements of the task it is trying to accomplish, no more, no less.  We all agree that artificial light helps our society.  But since when did extravagant over illumination become acceptable.  Not only does light pollution affect the night sky, it is also a HUGE money waster!  Every year over-illumination in the United States alone costs the same as approximately 2 billion barrels of petroleum and consumes unnecessary fossil fuels that are not replenish-able.  Imagine how the cost of a gallon of gas could decrease if we didn’t over-illuminate our homes, businesses, and roads!

Fortunately, the solution for light pollution is relatively simple.  Taking the time to assess your lighting needs and using the proper wattage and shielded fixtures will go a long way in reducing the amount of artificial light we send up into the night sky.  Using shielded fixtures ensures that the light only goes where it is needed:  the ground.  This also allows for a lower watt bulb to be used and that in turn reduces the amount of light reflected back off the ground.  Motion sensor are also useful to turn the light on only when there is movement.

Examples of various fixture designs  Source:  IDA

Examples of various fixture designs Source: IDA

Talking to neighbors about their lighting in a polite but concerned way is a great way to introduce the topic to them.  Writing to legislators can be effective as well.  There have been a number of municipalities that have incorporated lighting regulations into state, county, or local code in recent years.  There is a bill in Maryland that is currently in the General Assembly that would require all new light fixtures purchased by state agencies to be fully shielded.  The biggest hurdle we have to overcome is simply making people aware that there is a problem.  Many people don’t even think about the light they see at night or how their lights are contributing to the pinkish glow we know all too well.  In order to reverse the effects of light pollution we must use word of mouth to let people know that light pollution is real and it is diminishing the beauty of our night sky and wasting money in the process.

If you’d like to learn more about the issue of light pollution please read some of the other posts I’ve written on this blog and visit the International Dark Sky Association’s website  Together we can put a cap on light pollution and restore the beauty of a star-filled sky!



Dark Skies

Over the past century there has been one major casualty of urbanization and and afterwards urban sprawl:  dark skies.  The over-illumination of cities, suburbs, and now even rural towns has caused most Americans to completely forget about the night sky.  A majority of the people born since 1950 probably have never seen the spiral arm of the Milky Way or the galactic center at night and it is most likely a forgotten memory to those over 70.  Many people living in cities are lucky to be able to see Polaris and even Sirius, if anything at all.  For those downtown, the sky is a dark purplish-pink color all night long.  I live in Perry Hall, MD which is a suburb of Baltimore approximately 10 miles from downtown.  My favorite dark sky site so far is in Jarrettsville, MD which is about 25 miles from Baltimore and the pinkish glow from the city is still very much visible in the southwest washing out almost all the stars on the horizon. Astronomers daily feel the pain of light pollution, but so do all citizens in the country, not in their telescopes but in their wallets.

KingKey Tower in Shenzhen, China. Is that REALLY necessary?

On average each year over-illumination of cities and towns wastes an amount of energy equivalent to that of over 2 million barrels of petroleum!  That is mind blowing!  Imagine how much cheaper your gas could cost if we didn’t use streetlights that send their light straight up into the sky or if we kept those skyscrapers more dimly lit!  Your city or municipality could save a ton of money on energy if they just used it wisely!  The worst part about over-illumination is that most of the light pouring from our cities absolutely goes to waste.   The light wasted shoots upward into the atmosphere where it creates a haze of unnatural color in the night sky obliterating all but the brightest stars from view and jacking up energy rates and emptying your pockets.

There are many viable solutions out there to reduce the amount of light pollution in our skies.  However, since lawmakers and society in general are unwilling to accept an overhaul to the way we light our lives, and overall slow moving, any meaningful change looks unlikely in the near future.  It is projected that by 2025 over 75% of the country will not have access to a reasonably dark sky, compared to slightly less than 50% today.  Although, compared to Europe we’re slightly ahead of the game.  Less than 10% of Europeans have access to a dark sky that is viable for star viewing, let alone astronomy of any sort.   It is an extremely sad consequence of the culture we live in today where technology and human achievement come before natural beauty.

Many towns a few cities across the country already use energy and waste efficient lighting on streets, shopping centers, retailers, and homes but in order for any noticeable progress to be made a nationwide effort must be started.  It begins with installing waste reducing lights along highways and streets in major cities.  Lights that filter the particles straight downward onto the area desired instead of shooting it in all directions.  This would allow for less powerful lights to be used since the needed light is focused directly toward its target.  People will next complain that such an program would be too costly to implement but in reality prices for efficient lighting have dropped over the years as more people utilize them.  Now the price gap is almost negligible.  To stay brief, the point is that efficient and environmentally friendly lighting is highly attainable and has great potential to improve and preserve the natural beauty of the night sky.The various levels of light pollution.  The vast majority of Americans live in the brightest three levels

As is the case for all civic issues, the best thing to do is to contact your lawmakers and let them know where you stand.  You can even suggest to them that they propose a piece of legislation in session.  If you live in Maryland the legislative session begins on  1/12/12 (this Thursday).  You can also visit websites such as to learn more about light pollution and potential solutions.  Organizations like the International Dark-Sky Association need all the help they can get so do what you can and take action!

Lighting suppliers such as are also taking steps to educate the public about the effects and solutions of light pollution.  Companies such as LampClick that are aware of the problem and willing to offer solutions should be seriously considered when designing outdoor lighting for your home or business.

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