2023.10.17 Noriko HIgashi
Kozushima-Island is the second island in Japan to be certified as a starry sky protected area by the International Dark Sky Association in 2020. The island is working to create a town free of light pollution by replacing street lights that do not send unnecessary light into the sky. Through a workshop, we found out how the villagers feel about the nighttime environment that has changed as a result of these efforts.
The International Dark Sky Association is a group of astronomers, doctors, and environmentalists from around the world working to address the problem of light pollution. It grants certification called International Dark Sky Places to cities and places around the world that have taken measures to prevent light pollution. The hurdle is high, as they have to clear fairly high standards to be certified.
Kozushima-Island received that certification in 2020. About 600 streetlights and security lights on the island were replaced with ones that do not leak light into the sky. The color temperature was also standardized to 2700K. In addition to protecting the starry sky, sea turtles, which have not been seen for decades, have been seen laying eggs, greatly contributing to the improvement of the surrounding ecosystem.
Residents’ reactions to the replacement of the street lights were generally positive, with many saying that they were comfortable because the white, overly bright lights were gone. However, some said that they felt unsafe in some areas because of the darkness, so we actually went out into the city and walked around, discussing with local residents which areas made them unsafe or comfortable. It was a surprise to see that all the streetlights we saw had the same color temperature, and no matter which corner of town we turned, the streetlights emitted the same color, creating a peaceful nightscape of Kozushima-Island.
The dark spots found in various parts of the town are really dark underfoot, but they are also spots where one can look up at the sky and see a star-filled sky. Since the distant sight of a streetlight gives a sense of security and allows us to see the starry sky, instead of adding a streetlight, we experimented with installing a footlight that would not affect the starry sky, and actually illuminated only the foot area from a low position. We were also surprised to find that the lighting from the side of the vending machines we encountered in various places in the city was a nice touch.
Although there is no upward light from street lamps, some areas feel glaring. The participants were quite surprised to discover that the glare in their eyes made their surroundings seem darker, and that if they covered the glaring areas with their hands, they could see their surroundings better.
This was the first experience for all participants to walk while looking at the lights. The workshop was a good opportunity for the participants to reaffirm that Kozushima-Island is a valuable place with well-maintained street lighting that is not found anywhere else, and to experience how they can improve their concerns with a little ingenuity. (Noriko Higashi)
