So what colour is Uranus really? Options

[karolp]

Photos from the Voyager era show it to be on the border of blue and green, particularly greenish in some of them. On the other hand, amateur astronomers report from their backyards a definite "blue blob". So what colour would Uranus appear to human eye? Was the greenish tint made up as a distinction from Neptune? Or was it some flaw in image processing?

[Rob Pinnegar]

Those occultation pictures are neat but I'm sure they've been altered a little. Look at how bright Uranus appears to be, compared with the limb of the Moon! Although Uranus is probably several times more reflective than the Moon, it also gets 400 times less sunlight. I expect its brightness has been increased to make it more visible.

A lot of kids' astronomy books portray Uranus as green and Neptune as blue, but (as has been pointed out above) this is probably just "artistic license" to help children distinguish them from each other. Uranus is blue, but it's not as blue as Neptune -- it has that touch of green to it which Neptune pretty much completely lacks. More of a cyan-blue.

[JRehling]

A lot of kids' astronomy books portray Uranus as green and Neptune as blue, but (as has been pointed out above) this is probably just "artistic license" to help children distinguish them from each other. Uranus is blue, but it's not as blue as Neptune -- it has that touch of green to it which Neptune pretty much completely lacks. More of a cyan-blue.

I agree. I've seen Uranus and Neptune in very tight succession (within 5 minutes) of each other, and the difference (besides the very large difference in brightness) was obvious: Uranus is greener... but still blue-green, not out-and-out green.

I've also seen Uranus and Mars in rapid succession, which is an astonishing difference in color -- in some respects, the largest difference in color you can see in the sky without developing a long exposure of something or other.