Fine structure of the celestial polarization pattern and its temporal change during the total solar eclipse of 11 August 1999

Polarization transition between sunlit and moonlit skies with possible implications for animal orientation and Viking navigation: anomalous celestial twilight polarization at partial moon

“…This is demonstrated well by the example of foraging/flower-visiting honeybees (Apis mellifera) that failed to return to their hive after a 2 min period of a total solar eclipse [40][41][42]. Not only the celestial distribution of intensity and color, but also the patterns of degree p and angle α of skylight polarization, change drastically during the totality of solar eclipses due to the considerably altered illumination conditions [23][24][25]. The degree of polarization p of light from the eclipsed sky is usually considerably reduced, and if it becomes lower than the threshold p of polarization sensitivity of a given species navigating on the basis of sky polarization, the animal can disorient itself.…”

“…The degree of polarization p of light from the eclipsed sky is usually considerably reduced, and if it becomes lower than the threshold p of polarization sensitivity of a given species navigating on the basis of sky polarization, the animal can disorient itself. Furthermore, even if p > p during totality, the α pattern of the eclipsed sky differs so greatly from that of the normal sky [23][24][25] that polarization-sensitive animals inevitably disorient themselves when they try to navigate by means of this altered celestial α pattern. Bernáth et al [41] suggested that one of the reasons for the odd disorientated behavior of Apis mellifera and their mass perishment (10%-15% of a hive) observed during a total solar eclipse [40,42] may be the unnatural polarization pattern of the eclipsed sky: prior to their flower-visiting flight, honeybee workers fuel up their stomach with an appropriate amount of honey, being proportional to the distance to be traveled from the hive to the nectar source and back to the hive.…”

“…The distribution of skylight polarization has been investigated under clear [9][10][11], partly cloudy [12,13], overcast [14,15], foggy [15,16], and smoky [17] sky conditions as well as under tree canopies [18]. The polarization characteristics of the sky were also measured under such extreme conditions as total solar eclipses [19][20][21][22][23][24][25] and at the edge of ice-sea on the high Arctic [26]. Sky-polarization patterns were also investigated during moonless twilight [27] and at full moon [28].…”

Neutral points of skylight polarization observed during the total eclipse on 11 August 1999

“…In spite of the scientific popularity of total solar eclipses, which appear almost every year somewhere on the Earth, the empirical knowledge accumulated about the polarization patterns of eclipse skies is rather limited, since the earlier polarization measurements were restricted to one single point in the sky or at most to the solar-antisolar meridian. Because of the recently developed methods of full-sky imaging polarimetry [11][12][13][14][15][16][17][18][19] the final impediment was removed for measuring the polarization pattern of the entire sky dome under the extreme illumination conditions occurring during the short period of a total solar eclipse. The first full-sky imaging polarimetric study of the eclipse sky was performed by Pomozi et al 16 on 11 August 1999 in Hungary.…”

Polarization of the Sky

“…Scattering of sunlight produces patterns of partially linearly polarized light in the sky throughout the day (Brines and Gould 1982;Können 1985;Coulson 1988;Pomozi et al 2001a;Horváth and Varjú 2004;Suhai and Horváth 2004), and similar patterns appear at night when the moon is bright enough ). This celestial polarization pattern is used for orientation by many animal species (Horváth and Varjú 2004).…”