Umbriel and Ariel, the moons of planet Uranus, were discovered by English astronomer William Lassell on 4th October 1851. Lassell had also discovered Triton, the largest moon of planet Neptune on 10th October 1846.
Umbriel and Ariel, the moons of planet Uranus, were discovered by English astronomer William Lassell on 4th October 1851. Lassell had also discovered Triton, the largest moon of planet Neptune on 10th October 1846.