Great Red Spot (GRS) A large oval feature in Jupiter's clouds at about 22° south latitude. Its dimensions are about 26 000 km east–west and 14 000 km north–south. It was first recorded by S. H. Schwabe in 1831 but attracted little attention until 1878–82, when it became a striking dark red. Since then it has varied greatly in size, colour, and intensity, sometimes being so faint that it is detectable only by the hollow it makes in the South Temperate Belt (the Red Spot Hollow ). A prominent, slightly smaller dark spot at a similar latitude to the Great Red Spot was seen in 1664 by the English scientist Robert Hooke ...