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  • Writer's pictureLuke

Light Pollution

Updated: Apr 30, 2021

You probably already know what light pollution is, the term is fairly self explanatory. But just in case; Light pollution is why you can see more stars in the mountains rather than in the city. All of our outdoor lights (street lights, flood lamps, neon signs, etc) send a bit of their light directly up towards the sky. With the amount of outdoor lights in a city this adds up so much that it drowns out all but the brightest celestial objects.

Best shielded light fixtures to lower light pollution.

It may be unlikely that we will ever be able to see the milky way in downtown Denver. However, every little bit helps and hopefully we can preserve the few dark areas we have left.

Lowering light pollution is a cause anyone can get behind. I've seen many people that don’t usually agree on anything come together to agree light pollution is a bummer. I’ve never met someone who wished to see less stars in their hometown. From Texas where “the stars at night are big and bright”, to Hawaii which probably has the strictest light ordinances of any state. Light pollution is undeniable and has a very obvious source, light. So let's discuss how we can lower our impact on the night sky.

A comparison of the view of the night sky from a small rural town (top) and a metropolitan area (bottom). Light pollution dramatically reduces the visibility of stars.

The solution is as obvious as the problem; just make less light. Be sure any outdoor light you use is pointed down towards only what you are using it for, and on only on when it’s in use. There’s tons of options to do this; motion sensor lights, low light pollution LEDs, shielded fixtures… this all might be sounding high tech and expensive but it actually pays to lower light pollution.

Having your lights on motion sensors makes your property more secure, and lowers your electric bill. LED lights are more efficient lowering your electric bill and the ones that are especially good for lowering light pollution have a warm amber hew, that cause less eye strain. Shielded fixtures give you more bang for your buck! Rather than having half the electricity your bulb uses wasted on going up to space, a shielded light fixture takes that otherwise wasted light and reflects it down where it’s more useful.

Best lights to lower light pollution

One of the biggest myths of why you need lights always on outside is security. There is no evidence that lights prevent crime. Let me say that again: outdoor light has no effect on crime. There’s actually indication that the opposite is true; the absence of light prevents crime. When lights are on 24/7 criminals will take that as a sign that no one is home as they expect lights to turn off and on while in use. Also in the absence of light criminals have to use flashlights which catches the eye of neighbors/bystanders more leading to more criminals being caught/stopped. Don't just take my word for it: source, source 2, source 3, (Source X: do your own research search something like "Does outdoor lighting reduce crime?")

Motion sensor lights are better for security as you are alerted by seeing the light turn on that someone might be in your yard, bringing you to the window (usually to see a fox/raccoon tail darting off into the night). This shows the most effective form of security; community! The best way to secure your home or business is to get to know your neighbors. If your neighbors know you and are generally aware of your usual routines they will be the first to recognize when something suspicious is happening around your property (i.e. your motion sensor light turning on, or suspicious flashlights on your property) and will be able to alert you/authorities.

Community is also the solution to light pollution! If everyone reading this took steps to reduce their light pollution there will be a slight effect but that effect will be greatly increased if you and your neighbors, and your neighbors neighbors, and your neighbors neighbors neighbors, and so on all caught on. Hopefully enough neighbors will catch on and you'll be able to see the milky way from your back yard! Go next door and meet your neighbors! If you both wear your mask and just chat through the screen door this can be done relatively safely. Maybe also pass along this article and talk to them about doing a tour together to appreciate the night sky more.

most everyone can see the brightest stars of Orion in their local park/backyard but only the darkest communities can see the milky way going thru Orion.

To get this going we’re offering to split the cost of any lighting upgrades you and your neighbors do. If you upgrade any lighting fixtures in the month of April, May, or June 2021 send me a picture of the light (before and after photos that I can feature on social media are preferred but if you don’t want me to share your pictures just let me know), and a photo of the receipt. I will send a discount of half the price of the lighting fixture up to 40$ (full price of a tour!). For example if you upgrade all your outdoor lights with motion sensors and LEDs for 40$ you will get a half price tour (40$/2 = 20$ off). If your neighbor spends 80$ replacing all of their outdoor lights with top of the line low light pollution lights they can get a tour for free (80$/2 = 40$ off)! This on top of the electricity/security savings from upgrading your lights means they will pay for them selves in no time! And of course seeing the stars in your back yard is priceless!

That’s the “carrot” and is my preferred way to lower light pollution but there’s also a “stick”.... Most places will have light pollution laws. Usually they are 'lighting ordinances' in the city’s zoning codes but sometimes will be in the county or state level. It’s definitely worth searching “[your city/county/state] lighting ordinance”. If you don’t find anything write your local representatives to get the ball rolling on getting some to protect the sky above your community. Luckley Boulder has really strong light ordinances that are easy to find, here:

In Boulder you can anonymously report outdoor lighting violations in their zoning violations hub here: under the “Code Enforcements” menu and "Zoning Code Violations" topic and let the city know if you would like to report an outdoor lighting complaint. It’s not like your neighbor will have their door kicked in by the light police but they might get a strongly worded letter from the city and possibly a fine if they don’t reduce their light pollution.

In my experience my complaints didn’t do anything. I tried to bring up the lights at Guardian Storage that are pointed directly up. I was told that they are approved which I still don't understand since they are pointed straight at the sky. My complaint can be found here: Don’t let this discourage you, I’ve only made that one complaint. I have heard a few success stories and plan to make another complaint soon. If you live in Boulder, drive around your neighborhood at night, take pictures of the worst lights and send them to Inquire Boulder, the worst they can say is tell you nicely “those are approved”.

More photos of bad lights around Boulder.

Finally that brings us to one of the worst light polluters, street lights. Unfortunately the deck is stacked against us here due to something called "base load". Base load is the minimum amount of power a power plant needs to generate so it doesn't damage the equipment. Power companies will make deals with municipalities selling this base load of power at a low price if, the city/county/state promises that they will use that power all the time. This is usually a good deal since cites have lots of buildings and infrastructure to power. However, at night they still have to use this base load of power so they'll turn to building more inefficient street lights to eat up this power.

Paris "the city of lights" from space. It's amazing to think that the observatory in Paris once made so many significant observations with its location in Paris.

There is hope as more green sources of energy (wind/solar) don't have the base load problem as much. Hopefully as we start switching the grid to these green sources economic forces will push municipalities to use more efficient street lights. Again, the best you can do is write your local representatives to get the ball rolling on protecting the sky above your community. Let me know if there's anything I can do to help! I can also write your representative as a small business owner that depends on dark skies. Possibly we could even put together an astronomy program to highlight the importance of preserving the heavens above. Maybe you will find someone sympathetic; my old roommate grew up in a small town in Kansas where they put switches for the street lights at the end of his block so he could turn them off when he wanted to stargaze.

So go forth and be a lighting crusader! Talk to neighbors! Write your representatives! Report places that are creating too much light pollution! Take back our night sky! And don't forget to take part in our cost sharing deal this spring to lower the cost of upgrading your lights!

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