Turn Down the Lights, Turn Up the Stars

We are presently witnessing a rapid transformation of our outdoor nighttime environment as many older lighting sources such as high pressure sodium, metal halide, and fluorescent are being replaced with solid state lighting, specifically light emitting diodes (LEDs).  Many of the lighting decisions being made today with little or no citizen input will have consequences that impact our nighttime environment for decades.

Rather than continuing to subscribe to the “more is better, dusk-to-dawn” approach to outdoor lighting, we need to utilize this new technology in creative and innovative ways (many already available) to improve our nighttime built environment while minimizing lighting’s deleterious effects on the natural world.  Three paradigm shifts are needed.

Paradigm Shift #1
Less light will usually work just fine (a little light goes a long way)

Paradigm Shift #2
Dusk-to-dawn lighting → Lighting on Demand

Paradigm Shift #3
Full intensity lighting → Multi-Intensity Lighting (dimmable)

When choosing the amount of light you need, one should always consider the task or tasks needing to be performed.  For example, the amount of light needed to identify a rural intersection is much less than is needed to play a baseball game at night.  In both cases, though, the light needs to be restricted to only the area needing to be illuminated: the intersection or the playing field.

Another example.  When my wife and I bought a house in Dodgeville, Wisconsin back in 2005, our front porch had a 100-watt frosted incandescent light bulb to light the porch that we could turn on whenever we had company in the evening.  Thinking it too bright, we replaced the 100-watt bulb with a 60-watt bulb, then tried a 40-watt bulb, and finally a 25-watt bulb.  The 25-watt bulb adequately illuminated the porch and the stairs leading up to the porch, so in it stayed.

Then there is the issue of dusk-to-dawn lighting.  Many years ago, we switched outdoor lighting on or off as needed, but technological advancements later allowed us to have a light come on at dusk and stay on all night until dawn.  Now, think of all those lights burning when no one is there to use them.  If security is a concern, there is even newer technology that will do a far more effective job of detecting intruders than simply leaving a light on all night long.  In fact, a dusk-to-dawn light is not needed at all as part of an effective security system.  So, why not use 21st-century technology to have outdoor lights automatically turn on when needed and turn off when not needed?  Some LED light bulbs even come now with integrated occupancy sensors.  Lighting on demand could and should be replacing most dusk-to-dawn lighting within the next few years.

What about some roadway and parking lot lighting that must remain on all night long?  Those lights could be at full brightness during times of high traffic such as during the evening hours, but dimmed to 50% when traffic is lower, such as after midnight.  Once again, 21st-century technology makes this easy to do.

LED lighting lends itself very well to frequent on-off switching and dimming, but much of what is currently being installed is too blue.  As you can see in the table below, typical LED light sources have a substantial “spike” at the blue end of the visible light spectrum as compared with other white light sources.

Not only does blue light scatter more in the atmosphere and within our eyes, but many people perceive bluish-white light as colder, more clinical, than the warmer white light where this blue spike is absent, as shown below.  The blue spike in LED lighting can be removed either by using filtering, or by using a different phosphor that gives a warmer white spectrum.  Strongly preferred for both indoor and outdoor lighting are LED light sources with a correlated color temperature (CCT) of 2700K or 3000K.  2700K is the standard for indoor lighting, and yet 4000K is most often used for outdoor lighting.  Why?  Let’s move the standard for outdoor lighting to 2700K or 3000K.

By properly shielding lights so they only shine downwards, by using lights that are no brighter (or bluer) than they need to be, and by turning lights off when they are not needed—or dimming them during times of lower activity—we all will be helping to improve both our natural and celestial environment.

Turn Down the Lights, Turn Up the Stars *

* Suzy Munday, May 11, 2018

Additional Thoughts

In thinking about 21st-century lighting, one’s thoughts naturally towards 21st-century power generation.  We do not think often enough about the many advantages of a more decentralized power grid, where nearly everyone is generating some power with solar panels and small-scale wind turbines, as well as other local sources of energy such as geothermal.   As we once again consider building nuclear power plants (which will still be quite vulnerable to terrorism) and continue to build expensive fossil fuelish power plants and ugly high-voltage transmission lines, why not a paradigm shift towards decentralized energy production instead?

Illumination Levels: Then and Now

The following excerpts are from the 1911 and 1925 editions of A Text-Book of Physics by Louis Bevier Spinney, Professor of Physics and Illuminating Engineering at Iowa State College (now Iowa State University) in Ames, Iowa.

From the 1911 edition…

ILLUMINATION

516. The intensity of illumination of any surface is defined as the ratio of the light received by the surface to the area of the surface upon which the light falls.  A unit of intensity which is oftentimes employed is known as the foot candle, and is defined as the intensity of illumination which would be present upon a screen placed at a distance of one foot from a standard candle.  The meter candle is a unit of intensity which is employed to some extent.

The table below gives a number of values of illumination such as are commonly observed, the intensity of illumination being expressed in foot candles.

Suitable for drafting table    .    .    .    .    .    5 to 10

Suitable for library table   .    .    .    .    .   .    3 to 4

Suitable for reading table   .    .    .    .    .   .  1 to 2

Required for street lighting   .    .    .    .    .  0.05 to 0.60

Moonlight (full moon)    .    .    .    .    .    .   .  0.025 to 0.03

 

And from the 1925 edition…

ILLUMINATION

532.  The eye has a remarkable power of adaptation.  In strong light the pupil contracts and in weak light expands, so that we are able to use our eyes throughout a range of illumination which is really quite astonishing.  However, the continued use of the eyes under conditions of unfavorable illumination causes discomfort, fatigue, and even permanent injury.  Experiment and experience show that eye comfort, efficiency, and health considerations demand for each kind of eye work a certain minimum illumination.  Some of these illumination values taken from tables recently compiled are given below.

FOOT-CANDLES

Streets    .    .    .    .    .    .    .    .    .     .    .    .    .    .    1/20 to 1/4

Living rooms; Halls and passageways    .    .    1 to 2

Auditoriums; Stairways and exits;
Machine shops, rough work    .     .    .    .    .    .  2 to 5

Classrooms; Laboratories; Offices;
Libraries; Machine shops, close work    .    .    5 to 10

Engraving; Fine repairing work; Drafting;
Sewing and weaving, dark goods  .    .    .    .     10 to 20

 

By comparing the 1911 and 1925 data with the illumination levels recommended today by IESNA, we can see that recommended light levels for streetlighting have increased anywhere from 40% to 380% since 1925.  A cynic might say that we need more light than our ancestors did to see well at night.  As you may have noticed, light levels have been steadily creeping upward, everywhere, over the last few decades.

Recommended Illumination Levels for Streetlighting

Year        Minimum    Average    Maximum

1911             0.05                ???               0.60

1925           0.05               0.25               ???

1996          0.07                1.20               ???

Have you ever noticed how well you can see at night when the full moon is lighting the ground?  The full moon provides surprisingly adequate non-glaring and uniform illumination at just 0.03 footcandles!  For inspiration, take a look at the following text from an Ames, Iowa city ordinance, dated July 8, 1895:

“The said grantees shall keep said lamps in good condition and repair, and have the same lighted every night in the year from dark until midnight, and from 5:00 a.m. until daylight, except such moonlight nights or fractions of the same as are not obscured by clouds, and as afford sufficient natural light to light the streets of said city.”

This was originally published as IDA Information Sheet 114 in November 1996, and authored by David Oesper.

Dodgeville Street Project Proposals

As illustrated below, a lot of drivers in Dodgeville take a dubious “short cut” from King St. to Iowa/Bequette by way of W. Leffler instead of taking King St. all the way to Iowa/Bequette.  Most of the people taking this short cut are leaving Lands’ End and heading to their homes in the Madison metro area.  These folks are not Dodgeville / Iowa County taxpayers.  Here’s the problem.  W. Leffler has been beat all to hell and is badly in need of resurfacing.  All that Lands’ End traffic has contributed mightily to the degradation of W. Leffler.  Now, as a bicycle commuter trying to get from Lands’ End to most of the rest of Dodgeville (always a dangerous proposition), it makes sense to use W. Leffler to minimize the amount of time I have to ride my bike on busy King St. and very busy Iowa/Bequette.  But W. Leffler is so broken up that for safety reasons I need to ride near the middle of the road—but a steady stream of vehicles takes the short cut down W. Leffler instead of staying on King St. up to convenient entrance ramp to Iowa/Bequette.  It is a no-win situation for Dodgeville bicyclists.  One solution would be to have W. Leffler dead end at King St. with only a bike-path connector between King St. and W. Leffler, though I suspect that would be quite unpopular in our auto-centric community.  Another solution would be to resurface W. Leffler and never let it degrade this much again.  Is that too much to ask?  It is a short street, after all.

The Lands’ End Shortcut to the Madison Metro Area

I’m not a big fan of roundabouts, but if ever there was a case for one it would be at the intersections of Iowa/Bequette, N. Main, E. Spring, and W. Spring.  In my crude map overlay below, it looks like one building would probably have to be removed.  The roundabout would need to be designed to easily accommodate the comings and goings of fire trucks from the nearby fire station.  Presently, this “octopus” of an intersection is dangerous, and I completely avoid ever making a left turn there.  Why not prohibit all dangerous left turns at these intersections by installing a roundabout where every turn will be a right turn?

Where a roundabout is needed in Dodgeville

Falling Ice Chunks

There are a number of documented cases of large chunks of ice falling out of a clear blue sky.  After we eliminate ice falling from airplanes or nearby thunderstorms, there still appear to be some events that remain unexplained.

I first heard of this phenomenon over ten years ago, when a 50-pound chunk of ice fell through Jan Kenkel‘s roof in Dubuque, Iowa on Thursday morning, July 26, 2007.

These unexplained falling ice chunks are been given a rather inappropriate name: megacryometeor.  Why don’t we just call them “falling ice chunks”  or FICs for short, at least until they receive an explanation?

It almost certainly is some sort of unusual atmospheric phenomenon, as ice balls from space would vaporize before they reach the ground.

An unknown blogger (in Spain?) has been documenting news articles about all manner of falling ice chunks since the Dubuque event.  The blog is called HALS, which is the plural abbreviation for hydroaerolite—certainly a better name than “megacryometeor”—though this perhaps is also a geological term used to describe “silty sediments transported by the wind and deposited on a temporarily wet surface”.

Obviously, more peer-reviewed scientific research needs to be done on these falling ice chunks, megacryometeors, hydroaerolites, or what have you.

The LED Lighting Revolution

Solid state lighting, namely light-emitting diodes (LEDs), are completely revolutionizing indoor and outdoor lighting.  Here’s why:

  1. White LEDs on the market today have a system luminous efficacy ranging from 50 (least efficient) to 80 (average) to 140 (most efficient) lumens per watt.  This far exceeds the luminous efficacy of incandescent (5-35 lumens/watt), and generally exceeds compact fluorescents (45-60 lumens/watt).  Prototypes of the next generation of white LEDs have luminous efficacies up to 150 lumens/watt, and theoretically 200-250 lumens per watt may someday be achievable.  Since the traditional white light source of choice for outdoor lighting has been metal halide with a luminous efficacy of 65-115 lumens/watt, white LEDs are well on the way towards replacing metal halide.  Even the more efficient orange high pressure sodium (HPS) lights, with an efficacy of 150 lumens/watt, are nearly matched by the best white LEDs.  Only monochromatic low-pressure sodium (LPS) with an efficacy of 183-200 lumens/watt will give more lumens per watt than the best white LEDs.
  2. White LEDs last much longer than other light sources: 50,000 to 100,000 hours (between 12 and 24 years, operating dusk-to-dawn 365 days a year).  In comparison, high pressure sodium typically lasts about 5 years, and metal halide a little less at 4 years.
  3. Unlike high-intensity discharge (HID) sources such as metal halide, HPS, LPS, and mercury vapor, white LEDs are “instant on / instant off” with no warmup time to full brightness, so they can be switched on and off as often as you like with no shortening of bulb life; and they are easily dimmable. LEDs will render dusk-to-dawn lighting a questionable option rather than an operational necessity.

My only concern is that we finally “get it right” with LEDs instead of blindly following the “more is better” philosophy as we have with every lighting efficiency improvement in the past.  Low levels of white light (fully shielded to minimize direct source glare) is the most effective and efficient way to provide adequate illumination.  This shouldn’t come as a surprise, however.  Think of the light provided by a full moon as we have this week.

Unfortunately, most places that is not what is happening.  Light levels are increasing, as is the amount of lighting.  We seem well on the way towards eliminating anything resembling a natural nighttime environment for most people.  I don’t know about you, but that is not a world I want to live in.

References
DIAL (15 June 2016). Efficiency of LEDs: The highest luminous efficacy of a white LED.  Retrieved from https://www.dial.de/en/blog/article/efficiency-of-ledsthe-highest-luminous-efficacy-of-a-white-led/.

Kyba, C., Kuester, T., et al. 2017, Science Advances, 3, 11, e1701528

A Better Lotion Bottle

For many of us, winter in the Upper Midwest means dry, cracked hands and nasty splits at the ends of our thumbs and fingers.  The only way to avoid or at least mitigate this is to apply lotion to your hands after every hand washing, because soap removes too much of your skin’s natural moisturizing oils (lipids).

I’m not a big fan of pump dispensers when it comes to lotion.  When the pump has pumped all the lotion it can, there is still a lot of lotion left behind in the bottle.  And most of us don’t want to go through the extra effort needed to get to the remaining lotion, so we throw the bottle out rather than utilizing the remaining lotion and then recycling the bottle.

Wasteful lotion container on the left – Better lotion container on the right

Recently, just to see how much lotion was left in a Gold Bond® pump dispenser (excellent lotion, by the way), we used a razor blade to cut all the way around the midsection of the lotion bottle, separating it into roughly two halves.  Then we used a spoon to scoop out all the remaining lotion in the two halves and put it into a clean plastic tub—formerly a sour cream container.  The amount of leftover lotion is substantial, as you can see in the photograph below.  A many-days supply, to be sure!

Leftover lotion from a seemingly empty pump dispenser

We consumers need to put pressure on pump-dispenser lotion manufacturers to package their lotions in containers that make it easy to extract all the lotion.  Some lotion manufacturers are already doing this, and we should purchase their products.  O’Keeffe’s® Working Hands® is one good example.

You can get all of the lotion out of a container like this

Sometimes, lotion manufacturers package their product in both types of containers—pump dispensers and tub containers—but your local grocery store, pharmacy, or big-box store only carries the less environmentally-friendly pump-dispenser type of container.  Do your research, and meet with the store manager to ask them to carry the tub container alternative instead of—or in addition to—the pump dispenser.

Each and every day we can make choices that are better for our environment.  This is yet another example: use all the product and make it easy to recycle the container.

Plastic Recycling

That number you see within the recycling symbol on recyclable plastic is called the “resin identification code” or RIC.  One pet peeve: the recycling symbol and RIC are often too small, not easy to see, or are difficult to find.  Also, some plastics and plastic parts that could be recycled are not labeled.

The seven different types of recyclable plastics are listed below, along with a small subset of initial and recycling uses.  New applications for recycled plastics are being invented all the time!  Perhaps you have some ideas.

Polymer: Polyethylene terephthalate (C10H8O4)n
Other names & abbreviations: PETE, PET, polyester
Common uses: beverage bottles, fibers for clothing
Recycling uses: non-food containers, strapping, carpet fiber

Polymer: High-density polyethylene (C2H4)n
Other names & abbreviations: HDPE, PE-HD
Common uses: milk jugs, food containers
Recycling uses: plastic lumber, parking bumpers, recycling bins, sheds

Polymer: Polyvinyl chloride (C2H3Cl)n
Other names & abbreviations: PVC, V
Common uses: bottles, non-food packaging
Recycling uses: pipes, fencing, flooring, lawn chairs, wire insulation

Polymer: Low-density polyethylene (C2H4)n
Other names & abbreviations: LDPE, PE-LD
Common uses: plastic bags, six-pack rings, containers, snap-on lids
Recycling uses: packaging foam, plastic film, garbage bags

Polymer: Polypropylene (C3H6)n
Other names & abbreviations: PP
Common uses: food containers, medical & lab equipment, pill bottles
Recycling uses: pallets, trays, landscape borders, compost bins, bike racks

Polymer: Polystyrene (C8H8)n
Other names & abbreviations: PS
Common uses: plastic cutlery, disposable razors, CD & DVD cases
Recycling uses: packaging material, insulation sheets, park benches

Polymer: Other Plastics (acrylic, nylon, polycarbonate, etc.)
Other names & abbreviations: OTHER, O
Common uses: plastic lenses, food packaging & bottles, LCD screens, etc.
Recycling uses: plastic lumber, bus shelters, traffic lights, signs, etc.

LED Residential Streetlight Debut in Dodgeville: Too Bright!

A new bright white LED streetlight made its debut in Dodgeville, Wisconsin on Friday, November 3, 2017, and it isn’t pretty.

The white-light LED streetlight is located at the NE corner of W. Washington St. & N. Johnson St. in Dodgeville.  The illumination level on the ground peaks at 3.15 fc.  An existing orange-light high pressure sodium streetlight at the SW corner of W. Division St. & N. Virginia Terrace peaks at 1.23 fc, which is typical.

Even though the reduction of uplight and near-horizontal light (i.e. “glare”) from this luminaire is a welcome improvement, an illumination level 2.6 times as bright as before is neither welcome nor justified.  Furthermore, lower illumination levels may be acceptable when using white-light LED luminaires in comparison with high pressure sodium (Glamox n.d.).  More research is needed on the effect of spectral composition on both brightness perception and, more importantly, visual acuity at various illuminance levels.

I do not have an instrument to measure the correlated color temperature (CCT) of this luminaire, but visually it looks to me to be around 4000 K, which is too blue.  I will check with the City of Dodgeville and report back here.  The International Dark-Sky Assocation (IDA n.d.) and the American Medical Assocation (AMA 2016) recommend using “warm white” LEDs with a CCT no higher than 3000 K, with 2700 K preferred.

References
AMA (2016), Human and Environmental Effects of Light Emitting Diode (LED) Community Lighting H-135.927.  Retrieved November 5, 2017 from https://policysearch.ama-assn.org/policyfinder/detail/H-135.927?uri=%2FAMADoc%2FHOD-135.927.xml.

Glamox (n.d.), The Glamox Brightness Sensitivity Test. Retrieved November 5, 2017 from http://glamox.com/gmo-recreational/led-brightness.

IDA (n.d.), LED: Why 3000K or Less.  Retrieved November 5, 2017 from http://www.darksky.org/lighting/3k/.

Oesper, D. (January 9, 2017), Avoid Blue-Rich LED Lighting.  http://cosmicreflections.skythisweek.info/2017/01/09/avoid-blue-rich-led-lighting/.

Dark Sky Community Prospectus

  1. Rationale
    1. A small community (hereafter referred to as a dark sky community) can thrive without the need for streetlights or any other dusk-to-dawn lighting
    2. A dark sky community would appeal to people who value the night sky and a natural nighttime environment
    3. It will probably be many years before the majority of people will accept life without dusk-to-dawn outdoor lighting
    4. A dark sky community must be located far enough away from neighboring communities and other significant light sources that the night sky and nighttime environment will not be adversely affected, either now or in the foreseeable future
    5. It is better to live in community than in isolation
  2. Community Attributes
    1. A dark sky community should be multi-generational, but since rural employment options are limited, moving to a dark sky community may be easier for retired or semi-retired folks
    2. A dark sky community should be affordable, with a variety of housing options (units that can be rented, for example)
    3. An observatory commons area should be developed for observing and include more than one observatory for use by members of the community
    4. The dark sky community should engage in an ambitious educational outreach program, including the operation of an astronomy resort and astro-tourism business
    5. The business end of the community should be a nonprofit corporation or cooperative that operates the astronomy resort and rental properties
    6. The community should share resources as much as possible, freeing residents from the financial burden of having to individually own everything they need or use
    7. The dark sky community should engage in an ambitious program of collaborative astronomical research and data collection, working collaboratively within the community and with amateur and professional astronomers outside the community
  3. Community Location
    1. The most affordable option would be to “convert” an existing rural subdivision or small town into a dark sky community, current residents willing, of course!
    2. The best location for a dark sky community would be within, or adjacent to, a protected natural area such as a state or national park
    3. Recognizing that there would be distinct advantages in siting a dark sky community reasonably close to a town or city with medical facilities, it would be best (for astronomical reasons) for the dark sky community to be located southeast or southwest of the larger community
  4. Philosophy
    1. In an age of technological wonders such as digital imaging, computer-controlled telescopes, remote observing, and space astronomy, we recognize that there is still value in the experience of “firsthand astronomy” both for ourselves and our guests

For greater detail, see my astronomy village proposal for Mirador Astronomy Village.  I welcome your comments and ideas here.

Identifying Distant Light Pollution Sources

Ten years ago, I lived within easy walking distance of the south edge of Dodgeville, and on one starry evening, I walked to a favorite hilltop with a good view of the sky just south of town.  To my surprise and displeasure, I noticed a bright light dome in the southeast I had never noticed before.  Where was that light coming from?

Fortuitously, the bright star Antares was at that moment very close to the horizon, and right above the offending light dome!  I noted the time: 10:25 p.m. CDT on 15 May 2007.  And the observing location: 42° 57′ 06.4″ N, 90° 08′ 16.9″ W.

After getting home, I started up the Voyager planetarium software on my Macintosh, set the date and time to the observation time, and the observing location listed above.  I found that at that moment, Antares was at an azimuth of 134.2°.

Now, grabbing a protractor and a Wisconsin state map, I quickly determined that the most likely city along the 134.2° azimuth line from Dodgeville was Monroe, Wisconsin.  Though quite some distance away, could this have been the source of the light dome I saw?

Using a great circle calculation program on the internet and the known geographic coordinates (latitude, longitude) for the two locations using Wikipedia, I determined that Monroe is at bearing (azimuth) 133.5 from my observing location near Dodgeville at a distance of 35 miles.  This matched my star-determined azimuth quite well.

Was there an outdoor athletic event going on in Monroe at that time to cause so much light pollution?

Could the light dome possibly have been coming from Rockford, Illinois?  Even though Rockford’s bearing of 131.1° makes it a suspect, its line-of-sight distance of 71 miles makes this extremely unlikely.