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. 2024 May 31;7:671. doi: 10.1038/s42003-024-06304-4

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© The Author(s) 2024, corrected publication 2024

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

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Fig. 1 — a Map of sampling sites, landscape context (iconized), skyglow (background map layer) and respective lighting treatment (insets) in Germany. The map depicts the four study sites on the outline of Germany using data from a skyglow model⁵¹; 1. Experimental field site Westhavelland (upper right), rural site, very low skyglow (dark sky reserve), extensively managed grasslands, n = 12 luminaires per lit treatment, transition from conventional (LED, 3000 K) to tailored and shielded luminaires (LED, 3000 K)); plus dark control treatments (n = 12 unlit luminaires) 2. Municipal site Alter Flugplatz Karlsruhe (lower left), urban site, sand and rough grassland, extreme skyglow, n = 5 luminaires per treatment, transition from conventional luminaires (LED, 4000 K) to tailored and shielded luminaires (LED, 4000 K) 3. Municipal site Backofen Riedwiesen (upper left), suburban, very high skyglow, flood plain of Rhine river, n = 5 luminaires per treatment, transition from conventional (cylindrical HPS, 2000 K) to tailored and shielded luminaires (LED, 2700 K) 4. Municipal site Heimbachaue (lower right), rural, black forest, low skyglow, n = 4 luminaires per treatment, transition from conventional (bell-shaped HPS, 2000 K) to tailored and shielded luminaires (LED, 2700 K). Effect of a tailored spatial light field and additional shielding at the municipal site Heimbachaue. Left images (b, d) show conventional luminaires and right images (c, e) show tailored and shielded luminaires. The upper row (b, c) shows RGB images, the lower row (d, e) calculated luminance maps from the images in the upper row. Images were obtained on the same night from the same position in the center of the test site. The tailored luminaires emit light only on the target area (green arrows), while reducing spill light into adjacent areas (yellow arrows). A further tailored shielding reduces the light directly at the luminaire itself (red arrows). While the conventional road lights are visible from large distances, producing the highest luminance at luminaire heads (d, red arrows), the tailored LEDs are nearly invisible from a distance (e, red arrows). See Supplementary Figs. 6–16 for further RGB/drone images and spectral measurements). Landscape icons were made by Freepik from www.flaticon.com.