Original: At most oppositions, Hygiea has a magnitude which is four orders fainter than Vesta, and will require at least a 100 mm (4-inch) telescope to resolve, while at a perihelic opposition, it may be resolvable with 10x50 binoculars.
Simplified: At most oppositions, Hygiea has a magnitude of around +10.2, which is as much as four orders fainter than Vesta, and will need at least a 4-inch telescope to resolve.