Friday, June 2, 2017

Moonlight Towers

Photo Credit
























Above is an amazing photo of Southeastern Michigan tweeted by Astronaut Shane Kimbrough.  The cities of Detroit, Toledo and Cleveland are visible. The white glow of Detroit's new LED street lights clearly distinguishes the City.  

The blog below was written in December of 2012.  It describes Detroit's place in history as one of the first major cities to install street lights, or "moonlight towers" as they were called in the 1890s.

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There are over 85,000 street lights in Detroit and over half aren't working.  It was recently announced that a new Detroit Lighting Authority would be created in an attempt to make long over due repairs.

PLD Street light installed
at DHC's Emerald Springs

Despite their condition, have you ever stopped to notice the various designs?  I recently witnessed the installation of street lights at three Detroit Housing Commission (DHC) developments.  Surveying a few nearby streets quickly reveals quite a few selections ranging from older incandescent pendants to the typical white yellow glow of cantilevering low pressure sodium lamps.
Street light found in
Detroit's Harmonie Park

Street light found on
Gratiot Avenue


 












Doing a little research, I discovered that Detroit was one of the first cities to electrically light its streets.  The early solution was found in engineered structures nicknamed "Moonlight Towers".  Extremely bright lamps known as carbon arc lamps were hung from towers more than 150 feet in height.  Between the 1890s and 1910s, more than 120 towers illuminated 21 square miles of Detroit. Part of the system was sold to the City of Austin, Texas in 1895.  Today, one can still find 15 of these original Detroit towers illuminating various Austin neighborhoods.  Pictures can be found by going to this link: Andy Mattern Photography.

A moonlight tower  standing
in the foreground of Detroit's
Old City Hall circa. 1900
Lycurgus S. Glover


A working replica of a
 moonlight tower located in Zilker
Park, Austin, Texas built in 1967
Larry D. Moore CC BY-SA 3.0
The demise of Detroit's tower lighting system was caused by chiefly two developments around the turn of the century.  First, new construction technology enabled buildings (otherwise known as skyscrapers) to be taller than the towers.  Taller buildings meant less effective light distribution.  Second, the development of incandescent lamp technology. Though these early arc lamps were in fact more energy efficient than incandescent fixtures, they in comparison had poor light distribution patterns (including flickering), generated greater amounts of noise and heat (sometimes even sparks), and had shorter life cycles.

As we move into the second decade of the 21st century, street light technology is again improving as cities make the transition to cutting edge, energy efficient LED (Light Emitting Diode) technology.

Learn more about Detroit's early street light system by reading this article in Low Tech Magazine.