The Darkest Skies
in California

"Marginal site on a turnout with a view toward Crescent City but east almost enitriely blocked by trees and hillside. As time progresses trees to the west will block this view. However, on this date a reasonable monitoring site for Crescent City impacts. Seeing very good, transparency good. Sky is significantly impacted to the zenith because of proximity to town, but still fairly dark with good visibility of faint stars. Observer sick with chills and flu-like symptoms, no visual observations made."

"Remote and dark, nice protected location. Seeing good transparency good. Toward the west a bright and conspicuous broad light dome from Indio/Palm Springs/Beaumont/Los Angeles is the most evident insult to an otherwise excellent night sky. Barely discernable small light dome from Brawley/El Centro/Mexicali due south, and a faint glow over the mountains north from Las Vegas. Very good location for observing despite dirt road and little room for set up."

"Seeing good, transparency poor, very hazy. Lights from San Joaqin Valley cities subdued by haze and smoke, gradually clearing but very slowly as night progresses. Stars near the horizon almost extinguished, overhead pretty good sky, fairly dark. Airglow low plus extinction gives a very dark horizon sky to the northeast. SQM 21.66 1st, 21.74 2nd, 21.74 third, 21.76 fourth."

"Sky quality measurements were recorded at Kelbaker Road in Mojave NPres on 5/21/2017. The site demonstrated a scientific darkness reading of 21.78 SQM."

"Site on a bluff of lava, short walk from dirt road. Seeing good, transparency fair but improving as clouds dissapear, 25% first set, 5% along horizon 3rd set. Airglow low, very dark sky background. Klamath falls light dome to 15 degrees, glare of Tulelake causes unnatural land illumination on ridge tops, zlm 7.3 fairly easily, 7.6 glimpsed. Faint but large light dome west of Klamath falls near Mount Dome, Dorris?, very faint city to south east, maybe Alturas, early light bouced off clouds from city south of Mt. Shasta, quite faint. Bortle 3 mainly because of Tulelake. SQM 21.65 during 3rd set."

"Site on ridgeline northwest of fire lookout, accessible by foot on lookout road with small cross country hike to ridgetop. Outstanding location for astronomy, perfect monitoring site. Seeing excellent, transparency good. Very dark at zenith, small light domes from distant cities to north and east, main light dome from Eureka to southwest, bright but extends only to about 15 degrees above the horizon. The rest of the sky is essentially pristine. ZLM 7.2. Problem with camera all evening, finally connect but produces horizontal bands throughout. Unfortunate on such a perfect night. Some inversions visible along the coast, but no fog on land this night."

"Clear night, lots of scintillation"

"Slog through snow to reach summit, transparency good, seeing good. Light from Fresno/Visalia subdued by haze and fog in the valley. Sky at zenith pretty dark, zodiacal light faint above light domes to west, gegenschein barely seen near Jupiter. Looking to the northeast airglow very slight. Light domes fairly bright, degrade night vision, but turning away reveals an excellent sky. Two images on first data set not aligned, slightly darker because of instrument runaway, clouds to west in first data set reflect off light domes amplifying light pollution. Second data set excellent, only a small cloud remained over Fresno."

"Intermittent clouds"

"Very clear, steady, excellent night for Astronomy. Light domes brighter from valley cities than on 8/31/2005, presumably because of clearer air. Gegenschein not visible. Some smoke below summit, should not interfere. No clouds. Sky near zenith very dark, excellent detail in Milky Way, to south and west significantly degraded."