ization . ▁ ▁This ▁would ▁allow ▁the ▁navig ator ▁to ▁locate ▁the ▁sun , ▁even ▁when ▁it ▁was ▁obsc ured ▁by ▁cloud ▁cover . ▁An ▁actual ▁example ▁of ▁such ▁a ▁" s unst one " ▁was ▁found ▁on ▁a ▁sun ken ▁( T ud or ) ▁ship ▁dated ▁ 1 5 9 2 , ▁in ▁proxim ity ▁to ▁the ▁ship ' s ▁navig ational ▁equipment . ▁ ▁Non - pol ar ized ▁objects ▁Both ▁artificial ▁and ▁natural ▁objects ▁in ▁the ▁sky ▁can ▁be ▁very ▁difficult ▁to ▁detect ▁using ▁only ▁the ▁intensity ▁of ▁light . ▁ ▁These ▁objects ▁include ▁clouds , ▁sat ell ites , ▁and ▁aircraft . ▁ ▁However , ▁the ▁polar ization ▁of ▁these ▁objects ▁due ▁to ▁reson ant ▁scatter ing , ▁emission , ▁reflection , ▁or ▁other ▁phen omena ▁can ▁differ ▁from ▁that ▁of ▁the ▁background ▁ill um ination . ▁Thus ▁they ▁can ▁be ▁more ▁easily ▁detected ▁by ▁using ▁polar ization ▁imag ing . ▁There ▁is ▁a ▁wide ▁range ▁of ▁remote ▁sens ing ▁applications ▁in ▁which ▁polar ization ▁is ▁useful ▁for ▁detect ing ▁objects ▁that ▁are ▁otherwise ▁difficult ▁to ▁see . ▁ ▁Notes ▁and ▁references ▁ ▁Pol ar ization ▁Pattern s ▁of ▁the ▁Tw il ight ▁Sky . ▁C ron in ▁T . W . ▁et ▁al ., ▁ 2 0 0 5 , ▁S PI E , ▁ 5 8 8 8 , ▁ 3 8 9 ▁Pol ar ization ▁patterns ▁of ▁the ▁summer ▁sky ▁and ▁its ▁neutral ▁points ▁measured ▁by ▁full - sky ▁imag ing ▁polar imet ry ▁in