A canopy trap and aerial nets led to finding 8 species of Tabanidae. There was an abundance of calyptrate muscoid flies. Camel's Hump is in the Green Mountains of western New England, USA. Discovering Diptera on Camel's Hump involved sixteen visits over 40 years. Upwards of 23 other Diptera species are listed. Habitats on the east side and above 762 m (2500 ft) elevation on Camel's Hump differ ...

We present the first measurements of radiance spectra of rainbows. The bows on two sunny days (3 and 6 June 2008) were produced by the fountain in the Parque de las Ciencias, Granada, Spain, that consists of a rectangular perimeter of 40 spray nozzles. Optical thickness of the spray from each nozzle was approximately 0.5. Spectral purity of the primary bow was highest for orange and blue, reach...

The downwelling irradiance in water is highly variable due to the focusing and defocusing of sunlight and skylight by the wave-modulated water surface. While the time scales and intensity variations caused by wave focusing are well studied, little is known about the induced spectral variability. Also, the impact of variations of sensor depth and inclination during the measurement on spectral ir...

Balloon-borne Limb profiling of UV/vis skylight radiances, O3, NO2 and BrO: technical set-up and validation of the method F. Weidner, H. Bösch , H. Bovensmann, J. P. Burrows, A. Butz, C. Camy-Peyret, M. Dorf, K. Gerilowski, W. Gurlit, U. Platt, C. von Friedeburg, T. Wagner, and K. Pfeilsticker Institut für Umweltphysik, University of Heidelberg, Heidelberg, Germany Laboratoire de Physique Moléc...

As part of our ongoing research into the clear daytime sky's visible structure, we analyze over 1,500 skylight spectra measured during a seven-month period in Granada, Spain. We use spectral radiances measured within 3 degrees fields of view (FOV's) to define colorimetric characteristics along four sky meridians: the solar meridian and three meridians at azimuths of 45 degrees, 90 degrees, and ...

The visible and NIR maximum degree of polarization (DoP) of cloud-free skylight depends on many factors, including wavelength, sun zenith angle, surface reflectance, and aerosol properties. For clear-sky environments, radiative transfer models accurately estimate the sky DoP when each of these properties is well constrained. (The model used here was recently compared with full-sky polarization ...

Combining series of exposures with different exposure times made with a digital SLR camera and a fish-eye lens allow to create highresolution images that contain the full dynamic range of daylight, including the Sun, usable as scene background and for skylight illumination computation purposes. These High Dynamic Range (HDR) images can also be calibrated with a luminance meter, so the image dat...

It is widely accepted that Vikings used sun-compasses to derive true directions from the cast shadow of a gnomon. It has been hypothesized that when a cast shadow was not formed, Viking navigators relied on crude skylight polarimetry with the aid of dichroic or birefringent crystals, called "sunstones." We demonstrate here that a simple tool, that we call "shadow-stick," could have allowed orie...