Astronomy and Space

Bortle scale

The Bortle dark-sky scale (usually referred to as simply the Bortle scale) is a nine-level numeric scale that measures the night sky's brightness of a particular location. It characterizes the observability of celestial objects, taking into account the interference caused by light pollution. Amateur astronomer John E. Bortle created the scale and published it in the February 2001 edition of Sky & Telescope magazine to help skywatchers evaluate and compare the darkness of night-sky observing sites.

Also on this shelf

See also

• ▸Bart Bok
• ▸Cultural depictions of Andy Warhol
• ▸Atlas (rocket family)

Uncatalogued shelf

Text from Wikipedia; plate via Wikimedia Commons. Text CC BY-SA 4.0; plate freely licensed (see Commons). Source record. Images and catalogue data are reproduced from open-access collections.