Input (grade 7): At most oppositions, Hygiea has a magnitude of around +10.2, which is as much as four orders fainter than Vesta, and will require at least a telescope to resolve.
Output (grade 6): 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.