Visual Measurements of Atmospheric Transmission of Light at Night.

摘要

Measurements of the visual transmission of the atmosphere were made at night across Chesapeake Bay over a period of two years. A visual telephoto meter was used to measure the illumination produced at a distance of 8.77 sea miles by a series of calibrated light sources. Transmission values ranging between 0.4 and 0.9 per sea mile could be measured to an accuracy of plus or minus 2 percent with the equipment as installed. Lower values were outside the range of the equipment and higher values are not normal for transmission through air. Under stable atmospheric conditions the data obtained at night were in good agreement with direct observations of the daylight visual range made before sunset and after the following dawn.