The Fourth Trumpet
1/3 of the Sun, of the moon and of the Stars became dark and that caused. 1/3 of the day to be without light, 1/3 of the night also to be without light.
Take a look at the order of Creation in Genesis 1:1-2:3
The trumpet referred to here was a shofar which is a ram's horn which the Jews used for religious purposes and for warfare.
Background Reading:
Revelation 8:12
The fourth Trumpet
12 The fourth angel sounded his trumpet, and a third of the sun was struck, a third of the moon, and a third of the stars, so that a third of them turned dark. A third of the day was without light, and also a third of the night.