反薄明光線 Anticrepuscular rays

西の空に太陽が沈んでた時、東の空がこんな風景！なんで？東だよ？なんだろうこのミステリアスな現象ーって写真撮りながら思ってたけどさっきグーグル先生に教えてもらったのー　
「反薄明光線」っていうらしい！

Today's eastern sky at sunset time. I saw this a number of times in my life but coming from the west while sun is disappearing behind a cloud but this one coming from the east puzzled me today! Some googling led me to a phenomena called "Anticrepuscular rays".

*The picture is contrast enhanced to make it look more clear.