The Darkest Skies
in Pennsylvania

"Site on pullout of Skyline Drive, south sky pretty well blocked by hillside. Seeing good, transparency excellent. Bright light domes from D.C. and Front Royal dominate the north and northeast, but zenith is remarkably dark, revealing the brighter parts of the Milky Way easily. Gradient from horizon to zenith however. Milky Way invisible in dim areas like Monoceros and Gemini. Airglow appears brighter than normal because of high gradient from zenith, even toward the west where there are no bright light domes. Lots of bright glare from Front Royal, Winchester, core of D.C. light dome very bright, damages night vision, 20 degrees wide. SQM 21.33 late. NELM measured by Duriscoe but with spectacles, no contacts, in fatigued state, in Triangulum."

"Set up on dirt road near canons at Murphy-Chambers Farm. Sky is cloud free at start of data collection with some low clouds along the horizon appearing later in the evening. Very nice location for night sky viewing, as this site is blocked from all direct glare sources. Milky Way is washed out in the lower sky from skyglow. Charles Town is easily visible to the west, the metro areas of Baltimore and D.C. have a light dome up to 30 degrees. For the most part, this area is surrounded by very bright skyglow along the horizon, though the natural terrain produces shielding that allows for comparatively good viewing. An SQM reading of 20.39 around midnight."

"Set up camera in field at Caboose Farm about 200 yds SW of Camp Round Meadow. Numerous direct glare sources from local farms and a building at Camp Round Meadow. A few clouds around the horizon to start but skies cleared completely by third set. Very high humidity along with warm temps causing high extinction. Sky glow from Frederick easily visible, as is the greater Baltimore-D.C. area. Milky Way is barely visible and most deep sky objects not visible. Decent view of most standard constellations and the night sky is still markedly better than from within Frederick or other comparable cities."

"Sky quality measurements were recorded at Meadow south of Church House in Hopewell Furnace NHS on 8/16/2014. The site demonstrated a scientific darkness reading of 19.87 SQM."

"Site next to Wick House in a field north of the orchard. Seeing very good, transparency fair. Very humid, dew on the grass. No part of the sky is dark, a gradient of sky brightness from horizon to zenith. The sky is grayish white, near the NYC and Newark light dome some peach color seen. Very bright near the horizon, which is actually at least 10 degrees above the true horizon. The site is in a "hollow" and has tall trees all around, so the brightest parts of light domes are masked. No distinct "domes" are seen, the sky is bright all around except toward the west, which looks dark by comparison. It is therefore impossible to attribute light pollution to any individual city. The Milky Way is not at the zenith at this time of the year, but even late when the summer Milky Way is higher it is invisible. Near the zenith there are some features, the Coma cluster is seen as 10-12 stars, the form of Ursa Major and Leo are readily seen, but anything below 60 degrees above the horizon is severely compromised. The land is well illuminated, navigation easy unless you are looking toward New York and Newark, where the light of the sky produces glare. Estimate about 1/4 of scoptopic vision is lost, unless looking at the eastern sky, which is much brighter. Bortle Class 7, could be 6 later on if it gets a bit darker. With patience, remarkably ZLM of 5.9 is achieved."

"Clear, good transparency after front moved out. Many near-field lights and cars. Andromeda glimpsed with difficulty. SQM 18.36"