If you mean the Greek pronunciation, it is oo-rah-NOSS. (Stress on the last sylable, oo like in book, rah like in rather, NOSS like in LOSS.)
Ouranos meaning sky was the name of a Greek paganic god. Its latinezed form is
URANUS which in English shold be pronounced yuw-REY-nus. See also
URANIA and
OURANIA.