Astronomy Picture of the Day . ... Of course, the picture also shows something you won't see tonight -- a total lunar eclipse . A lunar eclipse is caused when the full moon enters Earth's shadow and as the eclipsed Moon's light grows steadily fainter, the Moon trail becomes narrow and dim. ... The refracted light lends the eclipsed Moon a dim and reddish appearance. ... Publications with keywords: Moon - eclipse - lunar eclipse . Publications with words: Moon - eclipse - lunar eclipse . ...