FoucaultFringes

October 5, 2014:  One Little Victory.....

       All text and images Copyright Michael E. Lockwood, all rights reserved.


It has been quite a while since I have had my 20" f/3.0 telescope out, and the reason was my neighbors' terrible energy wasting, light-polluting, glare producing, high-pressure sodium light.  It was a power company light, and I had not had time to do something about it until recently.  It was very bright out to a distance of 1/4 mile, and blindingly bright from my house, a mere 300 feet from the light.  It was the main source of local light pollution in my area.

Luckily, I'm a member of an electricity cooperative, the Eastern Illini Electric Cooperative.  This is a member-owned power company as is typical in rural areas, it is not a large company that is only interested in making money.

A while back (well... over a year ago) I had spoken to a kind man named Alan there, and I decided to call him again to see what could be done about it.

Alan, who was clearly a busy guy, took the time to have a fairly lengthy conversation with me.  I explained that my profession involved using telescopes on my property and also taking nighttime photographs.  I told him how the poor design of the light was disrupting both of those, as well as casting shadows in my own house, and that I had to put up thick curtains to block it.

I requested (not demanded, and I asked nicely!) that the current fixture either be fully shielded or replaced with a new, modern, shielded fixture.  We had actually tried to find a shield that light previously, but no shield would fit properly, so the only option seemed to be replacement.

I mentioned that many cities, towns, etc. were now only using fully shielded streetlights, which reduced glare tremendously.  This results in safer driving, more light getting to the road surface, and reduced energy costs.

I also mentioned the concept of light trespass - that is, light coming from one property spilling over onto a neighboring property - and that there was significant legal precedent in many states that basically says that your neighbor does not have the right to light your property.

Alan was concerned with how my neighbor might react, so I mentioned how this is a win-win situation.  My neighbors get all of the light coming out of the fixture going down onto their property, so they have better illumination of their property, and I don't have to suffer from the stray light from an outdated, poorly designed fixture.

A good summary regarding residential lighting with very illustrative photos can be found here:
Practical Guide for Residential Lighting

Here are some photos of the old light, taken from my south-facing deck.  (Yes, that's right, of course the light had to be to the south, where astronomers reading this immediately realize that many of the interesting objects in the sky are located.)  The first image below shows the light and the nasty artifacts (lens flare, etc.) that it caused when I tried to take photographs from my deck.

A high-pressure sodium light bomb

Below is a closeup showing the light.  Another light farther to the south is blocked by trees in the summer, but can be seen in the winter when the leaves are off the trees (it is seen to the left of the brightest light).

Closeup of the light bomb

It is obvious that even the tops of the trees are receiving quite a bit of light, so a large percentage of the light leaving this fixture is being wasted and is unnecessarily lighting up the sky and the undersides of clouds, birds and airplanes.

About two weeks later, I got a call from Alan informing me that they had purchased a couple of new LED street lamps as possible replacements for the unshielded light.  He said one of the employees had used a fixture at their own house and had really liked it.  He identified the new light as a GE Evolve LED street light.



About a week later I saw a bucket truck at the neighbors', working on the light!  That was fast!

I eagerly awaited nightfall, and a coincidence had it, some other astronomers were there to see it as well.

New light, not quite level

Close up of tilted lightI took some photos of the new light, and as you can obviously see, it was a massive improvement.  The cutoff nature of the fixture is evident in the photo above.  Why?  This was taken during harvest time, so there is a lot of dust in the air, and it shows the radiation pattern perfectly.

However, the fixture was still tilted upward in the direction of my house, as the old light had been, so it generated some glare and light trespass.  The image at right, taken with my longest telephoto lens, shows it more closely.  I knew is was not level because I could see a bit of the bulb from my deck.  With shielded lights, installing them in a level manner is critical to keep stray light from going in undesired directions.

So, very pleased but almost feeling a little bit guilty, I emailed Alan my thanks for getting the light replaced, but I also sent some photos to show that the installation was not done properly.  I requested (not demanded!) that the light be leveled properly when it was convenient for a lineman to do it.



Less than a week later I saw a bucket truck driving down the street, and crossed my fingers.  Sure enough, that night I could see that the light was now level, and the fixture itself was hardly noticeable - it was only shown by the reflection of light off the pole.  The result is pictured below.

New light, now properly leveled

Close-up of leveled lightAbove the light is seen, now nice and level.  Moonlight (just before the Oct. 8, 2014 lunar eclipse), illuminates the rest of the scene, and allows the top of the fixture itself to be seen.  The scene would be as dark as the images above if the moon was not up.

Now, ALL of the light is going where it should go - on my neighbors' property, and they are getting the maximum benefit of the new light.  I am seeing a minimum impact on my nighttime telescope use, photography, and general enjoyment of the night sky in my back yard, something that I have not experienced for almost two years.

Again, to the right here is a close-up of the fixture itself on the pole, and it is clear comparing to the one above that the light has been leveled properly.  This small change makes a significant difference since any direct light from the very bright bulb creates glare and makes one's pupil contract, harming their night vision.

This is quite literally the first positive sign that I have seen in the quest for more efficient, better nighttime lighting that preserves the beauty of the night sky, and it is literally in my back yard.  I have seen LED street lights popping up everywhere, and so long as they are installed properly, this could be a very good thing for energy efficiency (which is mainly why they are being installed) and for putting light only where it is needed.

Alan, on behalf of myself and my friends and neighbors who come over to use a telescope, shoot nighttime photos, observe a meteor shower, etc. at my house, thank you very much for listening to me and giving me my nights back.

Please check back for future installments of "In the Shop".

Mike Lockwood
Lockwood Custom Optics

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