Uranus and 4 moons (Roll over image for labels)   HOME INDEX BACK NEXT

The gas giant Uranus and its moons are about 1.8 billion miles from Earth, so they appear small when viewed through a telescope. The disk of Uranus is only about 4 arcseconds in diameter as seen from Earth. (As a comparison, our Moon has an apparent size of about 1800 arcseconds.) Still, the blue-green disk of Uranus is easy to see in amateur telescopes using high power. With a large enough scope, some of its moons can also be glimpsed. I have seen a few of them, with difficulty, through my 18-inch Dobsonian telescope.

The fifth brightest moon of Uranus, Miranda, was too dim and close to the planet to be visible on this night.

4-second exposures were used to capture the moons, and a 1/15-second exposure of Uranus was pasted into the image to avoid overexposing the disk of the planet.

  Diameter (miles) Magnitude
Uranus 15,759 5.8
Titania 980 14.1
Oberon 945 14.3
Ariel 720 14.3
Umbriel 730 15.0

Image details: A 1/15-second exposure of Uranus, and 22 4-second exposures of the moons, all at ISO 12,800, taken with a Canon T6i camera through a 14" Meade 850XL telescope at f/16. 

November 27, 2017