Huntsville’s Disappearing Dark Skies
Update: an earlier version of this post referred to the committee’s advice as an official recommendation. However, the committee never made an official recommendation and the guidance the city received was only derived from proposals presented by its participating members.
Huntsville, Alabama is know for space exploration, but recent changes to the City’s street lights will make it harder for its citizens to enjoy looking up into space. Last year, the city began installing new LED fixtures that are bluer, brighter, and unshielded.
The new lighting is particularly surprising because it contradicts proposals made by a committee formed just for this purpose. Continue reading to learn how this happened, and what you can do to help change it!
How it started
In 2019, the Huntsville City Council formed a committee of stakeholders to advise on new lighting ordinances. The committee was led by Huntsville Utilities and included representatives from the Von Braun Astronomical Society (VBAS), the US Space and Rocket Center, and other local institutions. The City Council’s goal was to adopt new LED lighting that reduced costs, while achieving a Bronze Level Dark Sky rating from the International Dark-Sky Association (IDA).
Among the recommendations made by members of the committee were:
- Restrict color temperature to 3000K or less
- Promote downward lighting rather than upward
- Promote the use of timers, dimmers, and motion sensors to limit unnecessary use of outdoor lighting
- Define both minima and maxima for lighting intensity
Due to the pandemic, the committee never made a united set of proposals to the City Council.
The committee was not the only group advocating for darker skies, however. A representative of a helicopter pilot group at Redstone Arsenal complained that night flight testing was made difficult by the growth of the City and street lights, especially those with unshielded lamps. A group of middle school students also petitioned the city council to reduce excessive lighting in an effort to protect bat populations.
Unfortunately, it appears that the recommendations of the committee and the community did not lead to results that most dark sky advocates would hope for. And residents are beginning to notice.
How it’s going
In the summer of 2021, the city began installing the new LED lights. While details may differ around the city, many of the newly install fixtures are the Cooper Lighting Caretaker™️ T5R-U0 model, with a C018 light engine (i.e. bulb) at 3000K color temp and 50W power, producing 7579 Lumens. While 3000K was the maximum color temperature recommended by the committee, this model results in more apparent brightness due to its other properties and the construction of the fixture. As shown in the picture below, these fixtures are unshielded.
The City could have chosen the C013, C015, or C016 light engine but opted for a brighter model. It also chose the Small Acrylic Refractor shield option, rather than the Zero Uplight Shield or Hillbrook Decorative Shield, which means more light is refracted upward into the night sky.
According to the City Engineering Department, the choice to use the Small Acrylic Refractor came after the city installed more than a thousand 50 W LEDs with the Zero Uplight Shield and citizens complained. This was probably due to the lack of a diffuser on the fixture, which meant the bare LED was visible. Part of the problem is the lack of a fixture choice with both a diffuser and shield by the manufacturer.
Furthermore, the light from the lamps may appear to the eye to be much brighter than the old lamps due to the number of lumens. The city could have opted for dimmer lamps and still achieve adequate illumination. Due to our physiology, humans see just as well in 25% illumination as we do in 100% illumination.
It’s not clear why the city largely disregarded the input from the committee. One possible explanation is that it chose instead to adopt the recommendations of the Huntsville City Police Department, which advocated for lighting with color temperature greater than 4000K. This may have been based on the incorrect belief that brighter light deters crime.
What can we do about it
The VBAS has started hearing complaints from its members, and many of them are asking what they can do to stop or rollback these changes.
Jeff Delmas, a member of the VBAS board and a member of the City Council committee, recommends that concerned citizens file an issue with the City through SeeClickFix and submit a photo to show the problem. It is against City codes for stray light to encroach into your property (it’s called Light Trespass).
Jeff himself has filed a SeeClickFix request, with good results. The city added shielding to a light post in front of his home, greatly improving the spray of light.
In February, the VBAS and Starry Skies South will participate in the IDA Globe at Night project. The project involves taking measurements of how dark it is (with or without a sky quality meter) and submitting results to a global database to see how lighting is changing across the world over time. Hopefully, these measurements will provide evidence our community can use to change the city’s direction.
Thank you to Jeff Delmas for providing much of the technical detail in this post, and helping to ensure its overall correctness.
