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Headshot of Emily Lakdawalla

30th anniversary images of Uranian moons

Posted By Emily Lakdawalla

02-02-2016 13:06 CST

Topics: trans-neptunian objects, New Horizons, pretty pictures, scale comparisons, amateur image processing, Charon, Voyager 1 and 2, Uranus' moons

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.

The moons of Uranus, to scale

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:

Oberon and Charon, compared

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.

Voyager 2's Oberon image catalog

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.

We must do better! For further reading, an entertaining article that appeared on today explains why Uranus is the best planet.

See other posts from February 2016


Read more blog entries about: trans-neptunian objects, New Horizons, pretty pictures, scale comparisons, amateur image processing, Charon, Voyager 1 and 2, Uranus' moons


nodyam: 02/02/2016 11:52 CST

Perhaps a thousand bumper stickers distributed to 100 cities, and carrying a blue green photo on a white background with the words, "Let's Go To Uranus" might stir up some awareness.

Mewo: 02/03/2016 04:58 CST

I think Oberon is more like Ceres than Charon. It has the same dark surface, crater saturation, and similar bright patches. It's only the coincidence of size that makes it like Charon.

Josh: 02/03/2016 06:44 CST

Concur with Mewo here...Oberon really doesn't have much in common with Charon beyond size and maybe composition (I'm willing to bet there is some sort of compositional gradient that allowed Pluto and Charon to have much more geological activity than most of the giant planet's moons...maybe more ammonia condensed in the kuiper belt?) However, Miranda and Ariel remind me a lot of Charon.

Atom: 02/03/2016 09:47 CST

Nice post Emily! The Oberon-Charon side by side is misleading since the respective radius's are 761-606 kms. A closer comparison might be with Umbriel / Ariel and Charon. (585/579 and 606 kms).

Therion: 02/04/2016 07:55 CST

I've made (very rough) comparsions of Charon with Titania and Oberon:

Therion: 02/04/2016 07:57 CST

Sorry, missing http http:// http://

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