YOU SAID:

i was walking down the street at night when i saw a butterfly fly towards the sky

INTO JAPANESE

夜の空に向かって飛ぶ蝶を見たときに、通りを歩いていた

BACK INTO ENGLISH

When I saw the butterfly to fly into the night sky, was walking down the street

INTO JAPANESE

夜空に飛ぶ蝶を見たときは、通りを歩いていた

BACK INTO ENGLISH

Was walking down the street when I saw a butterfly flying in the night sky

INTO JAPANESE

夜の空を飛んでいる蝶を見たときに、通りを歩いていた

BACK INTO ENGLISH

Was walking down the street when I saw a butterfly flying in the night sky