▁angle ▁of ▁polar ization ▁( or ▁polar ization ▁angle ) ▁is ▁defined ▁as ▁the ▁relative ▁angle ▁between ▁a ▁vector ▁tang ent ▁to ▁the ▁mer id ian ▁of ▁the ▁observed ▁point , ▁and ▁an ▁angle ▁per pend icular ▁to ▁the ▁scatter ing ▁plane . ▁ ▁The ▁polar ization ▁angles ▁show ▁a ▁regular ▁shift ▁in ▁polar ization ▁angle ▁with ▁az im uth . ▁For ▁example , ▁when ▁the ▁sun ▁is ▁setting ▁in ▁the ▁West ▁the ▁polar ization ▁angles ▁proceed ▁around ▁the ▁horizon . ▁At ▁this ▁time ▁the ▁degree ▁of ▁polar ization ▁is ▁constant ▁in ▁circular ▁bands ▁centered ▁around ▁the ▁sun . ▁ ▁Thus ▁the ▁degree ▁of ▁polar ization ▁as ▁well ▁as ▁its ▁corresponding ▁angle ▁clearly ▁sh ifts ▁around ▁the ▁horizon . ▁ ▁When ▁the ▁sun ▁is ▁located ▁at ▁the ▁z en ith ▁the ▁horizon ▁represents ▁a ▁constant ▁degree ▁of ▁polar ization . ▁ ▁The ▁corresponding ▁polar ization ▁angle ▁still ▁sh ifts ▁with ▁different ▁directions ▁toward ▁the ▁z en ith ▁from ▁different ▁points . ▁ ▁The ▁video ▁to ▁the ▁right ▁represents ▁the ▁polar ization ▁angle ▁mapped ▁onto ▁the ▁cel est ial ▁sphere . ▁It ▁begins ▁with ▁the ▁sun ▁located ▁in ▁a ▁similar ▁fashion . ▁The ▁angle ▁is ▁zero ▁along ▁the ▁line ▁from ▁the ▁sun ▁to ▁the ▁z en ith ▁and ▁increases ▁clock wise ▁toward ▁the ▁East ▁as ▁the ▁observed ▁point ▁moves ▁clock wise ▁toward ▁the ▁East . ▁ ▁Once ▁the ▁sun ▁r ises ▁in ▁the ▁East ▁the ▁angle ▁acts ▁in ▁a ▁similar ▁fashion ▁until ▁the ▁sun ▁begins ▁to ▁move ▁across ▁the ▁sky . ▁ ▁As ▁the