Fire moon

I was puzzled at the "fire moon" reference in Hobbit two, where Kili tells Tauriel about seeing a red moon rising. I don't remember any thing about this in Tolkien.

So what causes a "fire moon", where the moon turns red as blood?

UniverseToday discusses HERE


usually it is because it is low in the sky, but it can also be caused by smoke/particles in the air such as after wildfires or volcanic eruptions etc.

ZTResearch has a great photo of a firemoon in Rapid City from the wildfires in Wyoming. LINK


 a third reason is during a full lunar eclipse.