light trespass – Cosmic Reflections

Block Your Neighbor’s Light

If you have a neighbor with a dusk-to-dawn insecurity light or a glare bomb that happens to be turned on while you’re engaged in astronomical pursuits, I have come up with a solution.

In the photo above, you will see a Uline 6 × 6′ Welding Screen Shade 8 (H-4610S8). The Shade 8 black vinyl tarp is almost opaque¹ and does not have an objectionable odor, so you can store it in the house when not in use. I also ordered the optional set of four swivel casters from Uline (H-5388) so that the frame can easily be moved around by one person. One of these swivel casters is shown in the photo below.

I store the frame outdoors against the house under the patio roof. The canopy weight plates and frame’s minimal wind loading profile ensures that the frame will stay in place even in high winds. Once I roll the frame to the needed location to block the offending light, I use the canopy weight plates to keep the frame from moving while I am observing.

DSG Canopy Weight Plates from Dick’s Sporting Goods come as a set of four, and each one weighs 7.5 lbs. These keep the frame from moving during storage and when in use to block a neighbor’s light.

Since I wanted an easy way to hang the vinyl tarp on the frame and then remove it for storage inside after my observing session, I used four S-hooks from Ace Hardware. I used heavy-duty slip joint pliers to squeeze together the wide part of the S-hook that goes over the top of the frame so that it can’t come off of the frame. See the photo below.

To keep the S-hooks from sliding down off of the top of the frame, I made a couple of stops using Snake Wrap as shown in the photo below.

In addition to using the four S-hooks to hang the tarp, I also use a shoelace through the grommet nearest the top on each side to keep the tarp fully extended during light to moderate winds, as shown below.

In the final two photos, you see how the tarp moves as the wind blows against it. Allowing the lower part of the tarp to move when the wind blows reduces the wind loading on the light-blocking curtain.

Only a tiny amount of light gets through the Uline Shade 8 black vinyl tarp (i.e. you can see where the light is on the other side of the tarp if you look right at it). If the light you are trying to block is extremely bright and you require a completely opaque tarp, if you can’t find a suitable 6 × 6′ tarp with at least four grommets on each side, I’d recommend purchasing a 5′ 6″ × 7′ 6″ Heavy Duty Reflective All-Purpose Weather-Resistant 9 mil Tarp from Harbor Freight. You’ll want to fold the long side at the bottom and hook the flap to the rest of the tarp using cable ties through the grommets so the length doesn’t exceed 6 ft. ↩︎

Bad Lighting at Dodgeville High School

At a school board meeting in November 2017, concerns were raised about inadequate lighting for evening school events, so the Dodgeville School District directed Alliant Energy to install some additional lights. The lighting was installed during a warm spell in January 2018, and the photographs you see below were taken during the afternoon and evening of June 17, 2018.

Rather than being used only when school events are taking place in the evening, these terrible lights are on dusk-to-dawn 365 nights a year. They are too bright, poorly directed, poorly shielded, and the glare they cause on W. Chapel St. and N. Johnson St. could pose a safety concern for pedestrians not being seen by drivers experiencing disability glare. I can imagine that adjacent neighbors are not too happy with the light trespass into their yards and residences, either.

This is a perfect example of poor lighting design and unintended consequences. How could it be done better? Look for the solution below the following series of photos documenting the problem.

Bleacher path floodlight produces a great deal of uplight, and illuminates the disc golf course far more than the bleacher path

Bleacher path floodlight is mounted in a nearly-horizontal orientation

Bleacher path looking towards the bleachers

Bleacher path looking towards W. Chapel St.

Bleacher path floodlight lighting up the disc golf course. Also note how much brighter the illumination is from the newly-installed blue-white LED streetlight as compared with the orangish light from the older high pressure sodium (HPS) luminaire.

Bleacher path floodlight lighting up the disc golf course and basket

Large tree being brightly illuminated all night long with bleacher path in foreground

Sub-optimal parking lot lighting at Dodgeville High School

Two additional overflow parking lot floodlights

Overflow parking floodlight glare and spill light

Overflow parking floodlight glare onto W. Chapel St. in Dodgeville

Overflow parking glare and spill light onto W. Chapel St. in Dodgeville

Solutions

Pedestrian-scale 2700K LED “soft” lighting could be installed along the bleacher path

https://www.rabweb.com/images/features/ledbollards/bollard-hero.png — Or vandal-resistant bollards could be used—even low voltage lighting

If floodlights must be used, shield them, point them more downwards, and turn them off after 11:00 p.m. each night (or have them on only while evening school events are in progress)

In fact, regardless of the lighting solution, the lights should be either turned off or dimmed down to a lower level later at night. (Security cameras will see just fine at lower light levels if that is a concern.)

Good neighbor outdoor lighting means minimizing GLUT:

Glare—never helps visibility
Light Trespass—no point in putting light where it is not needed
Uplight—sending light directly up into the night sky is a total waste
Too Much Light—use the right amount of light for the task, don’t overlight

An Open Letter to an Unknown Neighbor

We haven’t met yet. I’m a non-confrontational kind of person (a typical Midwestern trait, I’ve heard), always eager to please and not to offend. But I want you to know how much your dusk-to-dawn floodlight bothers me. You see, I’m an astronomer. I even have a backyard observatory and I would love to show you the wonders of the night sky if you’re interested in seeing what’s up there. I’m probably the only person in Dodgeville or Iowa County doing astronomical research several nights a week, weather permitting. I accurately time when asteroids and trans-Neptunian objects pass in front of stars, blocking their light for fractions of a second up to several seconds. There is a lot we can learn from such events.

When I moved into my house, I had to install thick curtains in my bedroom because your bright light floods into the room all night long every night. In fact, your light floods into every window on the west side of my house.

I like it dark at night. It helps me to sleep better and, I’ve heard, sleeping darker is sleeping healthier. There’s even medical research that supports this.

Being an astronomer, I like to step outside and check the night sky from time to time, look at constellations—see if the northern lights are active. All of this is a struggle for me now. But it doesn’t need to be.

I think I know why you want to have this light. It seems you are trying to light the stairway from your backyard to your front yard for safety reasons when using those stairs at night. Have you considered putting those floodlights on motion sensors instead of a dusk-to-dawn timer? You’d save money on bulbs and electricity. Or, if you really feel you need the light to be on all night long, a better lighting system could be installed that would light your stairs without lighting up your neighbors’ houses and yards. Can’t afford it? I’m not wealthy either, but I’d be more than willing to pay for the lighting improvements, because I want to be a good neighbor and having a dark backyard and house at night means that much to me. Besides, one of the benefits of living in a small town in this beautiful area of rural southwest Wisconsin is getting a decent view of the night sky. No big city can compete with that.

I’ll even pay for us to hire a professional lighting engineer to do the job right so both you and I (and probably your other neighbors) will be thrilled with the results. I know enough about lighting to say confidently we will have a win-win situation. Guaranteed.

I’m looking forward to meeting you and discussing this. Thank you.