He said that he was fascinated by the changing colors of the setting sun, so he always spent some time watching it.

他说日落时变化多端的色彩使他看得入迷，所以他总是花些时间看日落。

youdao

The old man sat in the armchair, watching the sun setting down.

老人坐在椅子里，看着太阳落山。

youdao

Sun is a-setting in the west, , Angels watching over me, my Lord.

太阳在西方落下，，天使看守着我，我的上帝。

youdao

Cooling down in the lake, and then watching the sun setting over the dunes while soaking in a hot spring is a surreal experience.

BBC: Siwa: An Egyptian oasis