Chance to spot Uranus and Neptune

Posted on September 29th, 2010

Some planets are so bright as to be obvious in the night sky. But others are so dim that even many amateur astronomers go through life without ever seeing them.

Uranus on 25 September by Damian Peach

Uranus and Neptune are both giant worlds in the far reaches of the solar system which means they can never shine with the luster of, say, Jupiter or Saturn.

Uranus is, in theory, just bright enough to be spotted with the unaided eye when high up in a perfectly dark, moonless sky. It is much more readily seen with binoculars but you will need to know just where to look at to distinguish it from nearby stars.

Neptune, the furthest planet from the Sun, is considerably fainter but is again visible with binoculars or a small telescope.

If you have never seen Uranus or Neptune, now is a very good time to look because both are conveniently placed in the evening sky, though both south of the celestial equator. Uranus is particularly well positioned because brilliant Jupiter lies very close by – though this as a line-of-sight effect, of course, and the two worlds are at vastly differing distances.

You will find Uranus, at magnitude 5.7, shining just over a degree north of Jupiter as October opens in the constellation of Pisces. It reached opposition, when it lay in the opposite part of the sky to the Sun, on 21 September.

Neptune and moon Triton on 29 Sept by Damian Peach

Neptune, at magnitude 7.9, was at opposition on 20 August and may be found with the aid of a star chart in Capricornus near its border with Aquarius.

Don’t expect to see any details in the frozen clouds surrounding either planet because they show no more than the tiniest disks in standard amateur telescopes. Even the Hubble space telescope has been hard-pressed to record much detail anyway as the clouds are extremely bland compared to those of Jupiter or Saturn.

That fact makes all the more extraordinary the images shown here by noted British planetary imager Damian Peach. He made one of his regular trips to Barbados from where Uranus, Neptune and Jupiter are much higher in the sky and so less affected by atmospheric turbulence. The pictures, taken with CCD equipment through his Celestron C14 Schmidt Cassegrain telescope appeare to show mottling in the clouds of both planets. I asked Damian how sure he could be that these markings were genuine.

Where to find Neptune in October 2010.

He told me: “The darker banding area on the lower part of the disk of Uranus is a real feature, though the smaller features are inconclusive. For these images only light sharpening was applied. I’ve since produced a sequence of Uranus.

“The features on Neptune came out very easily and probably represent coarsely resolved detail. I am hoping to obtain a sequence of images of this also in the near future. Such images have been possible due to the excellent conditions and high altitude of these planets from where I obtained the images .”

• Discover space for yourself and do fun science with a telescope. Here is Skymania’s advice on how to choose a telescope. We also have a guide to the different types of telescope available. Check out our monthly sky guide too!


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