The Moonlit Princess

Speak to Seggin, who can be found on the west bridge of Zora's Domain. He will explain that he cannot forget the sight of Princess Mipha, holding her Lightscale Trident in the light of the moon. He wants to see that image of her just one more time. Once you've initiated this quest, journey to Shatterback Point, where the statue of Princess Mipha is placed. Wait for the moon to be up in the sky, about halfway up. Take a picture of the statue. Return to Seggin, and show him the picture. He will gift you a Zora Sword as a reward.