Streetlighting Concerns

I submitted the following letter to the editor to the Dodgeville Chronicle this evening:

Dear Editor:

Have you noticed the gradual transformation of our streetlights in Dodgeville, Mineral Point, and other communities in SW Wisconsin?  The light source in our streetlights is changing.  High Pressure Sodium (HPS), which has been in use for decades and produces a orangish-white light, is being replaced by light emitting diodes (LEDs), producing a whiter light.

What’s not to like?  LED’s many advantages include: efficiency, longevity, instant-on and instant-off, and dimmability, to name a few.  But Alliant Energy is installing new streetlights that produce white light that is too blue, and the illumination levels are about 2.6 times as bright as the high pressure sodium streetlights they are replacing.

Lighting specialists use a term called “correlated color temperature” or CCT (in Kelvin) that allows us to compare the relative “warmness” (redder) or “coolness” (bluer) of  various light sources.   The illumination provided by candlelight has a CCT around 1500 K, HPS around 2000 K, an incandescent light bulb around 2800 K, sunrise/sunset around 3200 K, moonlight around 4700 K, and sunny noon daylight around 5500 K.  The higher the color temperature, the bluer the light.

Higher color temperature illumination is acceptable in workplace environments during the daylight hours, but lower color temperature lighting should be used during the evening and at night.  Blue-rich light at night interferes with our circadian rhythm by suppressing melatonin production, thus reducing sleep quality, and several medical studies have shown that blue light at night increases the risk of developing cancer, most notably breast cancer.  Even low levels of blue-rich light at night can cause harm.  While it is true that something as natural as moonlight is quite blue (4700K), even the light of a full moon provides an illumination level of just 0.01 foot-candle, far dimmer than street lighting, parking lot lighting, and indoor lighting we use at night.

LED streetlights are available in 2700K, 3000K, 4000K, and 5000K.  I believe that Alliant is installing 4000K streetlights in our area—I certainly hope they are not installing any 5000K.  What they should be installing is 2700K or 3000K.  These warmer color temperature lights are no more expensive than their blue-white counterparts, and the slightly higher efficiency of the blue-white LEDs is entirely nullified by over-illumination.

Even considering a modest lowering of light level with age (lumen and dirt depreciation), these new LED streetlights are considerably brighter than the HPS lights they are replacing.  Just take a look around town.  What is the justification for higher light levels in our residential areas, and when was there an opportunity for public input?  In comparison to older streetlights, the new LED streetlights direct more of their light toward the ground and less sideways or directly up into the night sky, and that is a good thing.  But now the illumination level is too high and needs to be reduced a little.

If you share my concerns about blue-rich lighting and illumination levels that are often higher than they need to be, I encourage you to contact me at oesper at mac dot com.  I operated an outdoor lighting sales & consulting business out of my home (Outdoor Lighting Associates, Inc.) from 1994-2005, and wrote the first draft of the Ames, Iowa Outdoor Lighting Code which was unanimously adopted by the city council in 1999, so I am eager to work with others in the Dodgeville area who are also interested in environmentally-friendly outdoor lighting.

David Oesper
Dodgeville

Happy Birthday, AAAA!

The first meeting of the Ames Area Amateur Astronomers (AAAA) took place 40 years ago today: Saturday, June 2, 1979. Central Junior High Earth Science teacher Jack Troeger and Welch Junior High Earth Science Teacher Ron Bredeson held the first meeting in Jack’s classroom in the building that is now the Ames City Hall. This was a great start to a great astronomy club. Here’s to the next 40 years!

And, we just passed another important milestone in AAAA history. The grand opening of the original McFarland Park Observatory took place 35 years ago on Memorial Day, Monday, May 28, 1984. Back then, the pavement ended at the intersection of Dayton Rd. & County Road E-29, northeast of Ames, Iowa, and it was gravel the rest of the way.

The first McFarland Park Observatory with its second telescope, a 12.5-inch Newtonian & Cassegrain telescope. The first telescope was a 13.1-inch Coulter Odyssey Dobsonian.
Observatory manager Jim Doggett and AAAA president David Oesper inside the original McFarland Park Observatory. Lower right photo is Julie Oesper and Katie Dilks watching the spectacular aurora borealis display the evening of November 8, 1991.

The AAAA purchased a backyard-observatory silo-top dome from Glen Hankins in Nevada on Saturday, September 27, 1980, and then-Ranger (and later Story County Conservation Director) Steve Lekwa of McFarland Park was instrumental in allowing the AAAA to build its observatory at its present site at McFarland Park. The much-improved replacement roll-off-roof observatory, named after club members and benefactors Bertrand & Mary Adams, was completed in 2000. The only part of the original observatory structure that remains is the telescope pier!

Stevens Point

I visited Stevens Point, Wisconsin for the first time over the Memorial Day weekend and, I have to say, this community of 26,000 is impressive. A great place to stay while you’re there is the Baymont Inn & Suites at 247 Division St. N. It is a short and pleasant walk to the University of Wisconsin – Stevens Point campus, the Schmeeckle Reserve (wow!), and the Green Circle Trail. Michele’s Restaurant is only a few blocks down the street. Great food!

I miss living in a college town. It is energizing to interact on a daily basis with well educated, intellectually curious, and cosmopolitan people who are passionate about their work. I lived in Ames, Iowa—where Iowa State University is located—for nearly 30 years, and I feel more at home in Stevens Point, a smaller community, than I do now in Ames. I think Stevens Point is the nicest community I have visited since leaving Ames in 2005. Definitely would be willing to live there someday. UW-Stevens Point even has a physics & astronomy department, an observatory, and a planetarium. Perhaps I could help out in retirement.

Some towns have a lot going for them even without a college or university—around here, Mineral Point and Spring Green come to mind. Some towns are at somewhat of a disadvantage because they have a name that is not particularly attractive. For example, Dodgeville, where I currently live and work, has a moniker that isn’t all that inviting. But there is no place so nice to live as a college town—for people like me, at least.

My primary civic interests are in gradually developing a well planned network of paved, off-road bike paths, walking trails through natural areas, a center for continuing education, a community astronomical observatory, and a comprehensive and well-enforced outdoor lighting ordinance to restore, preserve, and protect our nighttime environment and view of the night sky. Living in a community like Dodgeville, I don’t get the sense that there is enough interest or political will to make any of these things happen. I can’t do it alone.

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.

Science News

Some people are molded by their admirations, others by their hostilities. – Elizabeth Bowen (1899-1973)

I have many admirations, and one of them is for a bi-weekly magazine called Science News.  My first introduction to this amazing publication was in 1973, when a friend of my recently-divorced mother, Frank Gillotti, started giving me his copies after he was finished reading them.  I was a sophomore at Hoover High School in Des Moines then, and by my senior year I was a subscriber for life.

Science News has been around a long time.  It started way back in 1922 as Science News-Letter, and remained that until 1966, when it became Science News.  Today, Science News has an international circulation of about 94,000—alarmingly, down quite a bit (like most magazines) from its peak circulation of nearly 250,000 in the late 1980s.  Unlike most magazines these days, Science News is not saturated with advertising, but is instead chock-full of well-written, accurate, and timely news and feature articles about all areas of science, technology, and mathematics.  Yes, astronomy and space science are covered thoroughly!  And, with each bi-weekly1 issue numbering 32 pages (though, occasionally 40+), it is easy to find the time to read or at least skim it cover-to-cover every two weeks.

In my early years reading Science News, one writer I particularly admired was senior editor / physics editor Dietrick E. Thomsen, whom I was so fortunate to meet at the AAS Meeting in Ames, Iowa in June 1986.  Sadly, he passed away in 1988.  One thing I remember about him besides his always-excellent articles was his passion for passenger trains, and his growing distaste for air travel at the time (and it has only gotten worse).  At that time, I had never ridden on a passenger train, but nowadays I ride Amtrak regularly, and love it!

Another fantastic writer in those days at Science News was space science editor Jonathan Eberhart (1942-2003) whose brilliant and unconventional career was sidelined by multiple sclerosis by 1991.  The AAS Division for Planetary Sciences (DPS) has awarded the Jonathan Eberhart Planetary Sciences Journalism Award annually since 2009.  J. Kelly Beatty (Sky & Telescope) was the first recipient (in 2009), and Emily Lakdawalla (The Planetary Society) won the 2011 award.

Science News maintains an excellent web site.  One feature I really like is they provide a complete list of sources and references for their magazine articles.

And, Society for Science & the Public (SSP), the nonprofit corporation that produces Science News, also produces an excellent website for readers ages 9-14, Science News for Students.

Check out these wonderful resources regularly, and while you’re at it, don’t forget to subscribe!

1Science News published weekly through April 12, 2008.  Science News began publishing bi-weekly on May 10, 2008.