January 24 was the 30th anniversary of the Voyager flyby of Uranus. Uranian moons have been on my mind ever since New Horizons sent us close-up images of Charon. The scarps and troughs and splatty craters on Charon reminded me of similar features we saw, though much less distinctly, in those Voyager photos. It seems the moons were on Ted Stryk's mind, too; on the occasion of the anniversary, he produced latest-and-greatest versions of the Voyager views of these worlds, posting each one at the Pluto Picture of the Day website. You can see Umbriel, Titania, Ariel, Miranda, and Oberon over there; here is a scale comparison of the six largest moons of Uranus.
NASA / JPL / Ted Stryk
The moons of Uranus, to scale
The major moons of Uranus to scale. These images were taken on January 24, 1986. The geologic diversity these moons show begs for another mission to explore them thoroughly. Sadly, we have never been back, and we have no plans to go back. Top row: Titania, Oberon. Bottom Row: Umbriel, Ariel. Top Middle: Miranda. Bottom Middle: Puck.
Check out how Oberon and Charon compare:
NASA / JPL / JHUAPL / SwRI / Ted Stryk
Oberon and Charon, compared
Oberon, moon of Uranus (left), and Charon, moon of Pluto (right). These worlds are of similar size and both exhibit intriguing geology. Oberon was barely glimpsed by Voyager 2 as it flew by the Uranian system on January 24, 1986, while Charon received a close encounter by the New Horizons spacecraft on July 14, 2015. Charon's complex geology makes the barely-studied moons of Uranus even more tantalizing.
As amazing an accomplishment as Voyager 2 was, and as artful the work that Ted has done is, it's frustrating that we don't have better images of these worlds. But this is what we've got. As a reminder, here is the entire Voyager 2 Oberon image catalog -- all the pixels we've ever taken that have resolved the moon as a geological world.
NASA / JPL / PDS Rings Node / montage by Emily Lakdawalla
Voyager 2's Oberon image catalog
Oberon is Uranus' second largest moon with a diameter of 1,522 kilometers. It is the farthest major moon from Uranus, so Voyager 2 only got a distant look during its January 24, 1986 flyby.