John E. Bortle is the creator of the Bortle Scale to quantify the darkness of the sky from 1 (urban inner city) to 8 (extremely dark rural area or national park, usually at high elevation, low humidity, and low wind).
John E. Bortle is the creator of the Bortle Scale to quantify the darkness of the sky from 1 (urban inner city) to 8 (extremely dark rural area). John E. Bortle is the creator of the Bortle Scale to quantify the darkness of the sky from 1 (urban inner city) to 8 (national park). This is usually at high elevation. This is usually at low humidity. This is usually at low wind.