sentence: Voyager 2 produced images showing the Great Dark Spot, a storm on Neptune, as it approached the planet in 1989. By the time the Hubble Space Telescope photographed Neptune in 1994, the spot had disappeared.
modified: fix grammar: Voyager 2 produces images shown the Great Dark Spot, a storm on Neptune, as it approach the planet in 1989. By the time the Hubble Space Telescope photograph Neptune in 1994, the spot have disappear.