How dark is the sky in Echternach?
Sky darkness for Mëllerdall Nature Park (20.82, Bortle 4), so far the only place in Echternach on Yozora Atlas, worked out from NASA satellite images of light at night (2025). The bright core of the Milky Way never climbs clear of the horizon haze in Echternach while the sky is fully dark; the rest of the band passes overhead, with the longest moonless nights from September to April.
Numbers like 21.95 or 16.97 are the brightness of the sky overhead on a clear, moonless night, in mag/arcsec². The scale runs backwards: a lower number means a brighter sky, from about 22 for a natural sky to about 17 in a city center.
How the readings are made
Darkest skies in Echternach
Among the places on this site. Plenty of land between them is just as dark, with no town or park to name it by.