The bloody sun, at noon,
Right up above the mast did stand
No bigger than the moon.

from Samuel Taylor Coleridge – Rime Of The Ancient Mariner on Rap Genius

Meaning

The sun is unusually small. it’s as if the light of the world is slowly fading. The bloody sun can imply a hell, in which the nature around changed as a punishment for Mariner’s sin.

To help improve the meaning of these lyrics, visit “Rime Of The Ancient Mariner” by Samuel Taylor Coleridge and leave a comment on the lyrics box