月げっ虹こう

noun

moonbow; lunar rainbow

A rare atmospheric phenomenon: a rainbow produced by moonlight rather than sunlight. Appears whitish to the naked eye due to low light, but long-exposure photography can reveal colors.

• 満まん月げつの夜よるに、滝たきのそばで月げっ虹こうを見みることができた。

  On a full-moon night, I was able to see a moonbow near the waterfall.