YozoraAtlas

How dark is the sky in Tennessee?

Sky darkness for 19 towns and parks in Tennessee, worked out from NASA satellite images of light at night (2025). 5 of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is Pickett Civilian Conservation Corps Memorial State Park (21.20, Bortle 4), the brightest Nashville (17.12, Bortle 8). Milky Way season in Tennessee runs March to September: on moonless nights the bright core stands clear of the horizon, climbing to about 26° at its highest.

19 Bortle class, 1 pristine to 9 city center park or dark-sky place city

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

NASA satellite night-lights map of Tennessee with every place marked

Darkest skies in Tennessee

Among the places on this site. Plenty of land between them is just as dark, with no town or park to name it by.

Brightest city skies in Tennessee

All 19 places in Tennessee

Amber names are parks and certified dark-sky places. The figure is the Bortle class: 1 darkest, 9 city center.

Bartlett8 Big South Fork National River and Recreation Area4 Chattanooga8 Cherokee National Forest4 Clarksville7 Cordova8 East Chattanooga8 Franklin7 Hendersonville8 Jackson7 Johnson City7 Kingsport8 Knoxville8 Memphis8 Murfreesboro8 Nashville8 Obed Wild and Scenic River4 Pickett Civilian Conservation Corps Memorial State Park4 Reelfoot Lake State Park4