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Arnott, J. T. (1982). Growth Response of White and Englemann Spruce Seedlings to Extended Photoperiod Using Three Light Intensities.
Abstract: Four seedlots of white spruce (Picea glauca (Moench) Voss) and three of Engelmann spruce (Picea engelmannii Parry), covering a range of 10 degrees of latitude and a range of altitudes, were sown in BC/ CFS Styroblocks and grown in a heated greenhouse and an unheated shadehouse, using incandescent light to provide a 19-h photoperiod. Four intensities of lighting were used: 0, 100,200, and 400 Ix. A second experiment with the same seedlots was conducted in growth rooms that were programmed to evaluate the effect of low night temperature on seedling shoot growth when the photoperiod was extended to 19 h, using a light intensity of 200 Ix.
Shoot length of white and Engelmann spruce seedlings grown under an extended daylength of 100 Ix were significantly taller than the control (0 Ix). There were no significant differences in shoot length or weight among the three intensities of light used to extend the photoperiod for all seedlots except the southern latitude-low elevation population of Engelmann spruce. The more northern populations of white spruce and the high altitude populations of Engelmann spruce did not require light intensities higher than 100 Ix to maintain apical growth. Low night temperature (7°C) did produce significantly smaller seedlings than the warm night (1SoC) regime. However, terminal resting buds of seedlings grown under the cool night regime did not form any sooner than on those seedlings grown under warm nights.
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Benn, C. R., & Ellison, S. L. (1998). La Palma night-sky brightness.
Abstract: The brightness of the moonless night sky above La Palma was measured on 427 CCD images taken with the Isaac Newton and Jacobus Kapteyn Telescopes on 63 nights during 1987 – 1996. The median sky brightness at high elevation, high galactic latitude and high ecliptic latitude, at sunspot minimum, is B = 22.7, V = 21.9, R = 21.0, similar to that at other dark sites. The main contributions to sky brightness are airglow and zodiacal light. The sky is brighter at low ecliptic latitude (by 0.4 mag); at solar maximum (by 0.4 mag); and at high airmass (0.25 mag brighter at airmass 1.5). Light pollution (line + continuum) contributes < 0.03 mag in U, approximately 0.02 mag in B, approximately 0.10 mag in V, approximately and 0.10 mag in R at the zenith.
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Cinzano, P. (2005). Night Sky Photometry with Sky Quality Meter. Technical Report 9, ISTIL. V1.4., .
Abstract: Sky Quality Meter, a low cost and pocket size night sky brightness photometer, opens to the general public the possibility to quantify the quality of the night sky. Expecting a large diffusion of measurements taken with this instrument, I tested and characterized it. I analyzed with synthetic photometry and laboratory measurements the relationship between the SQM photometrical system and the main systems used in light pollution studies. I evaluated the conversion factors to Johnson’s B and V bands, CIE photopic and CIE scotopic responses for typical spectra and the spectral mismatch correction factors when specific filters are added.
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Cleaver, O. P. (1943). Control of Coastal Lighting in Anti-Submarine Warfare.
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Ogden, L. J. E. (1996). Collision Course: The Hazards of Lighted Structures and Windows to Migrating Birds. Technical report, World Wildlife Fund Canada and the Fatal Light Awareness Program, Toronto, Canada., .
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