Can you see one of our Solar System’s outermost planets, Uranus, with the naked eye?

Fortunately,

It’s often stated that the planet Uranus is visible to the naked eye. However, if you ask someone whether they have actually seen it unaided, the answer you’ll normally receive is no. The reason for this is that this distant planet shines at the edge of naked-eye visibility and any direct views of it aren’t always conclusive.

Most of us live under less than perfect skies. An average dark sky will have a limiting magnitude – that’s the faintest star you can see – somewhere between mag. +5.0 and mag. +5.5. Country locations may push this further, perhaps down to mag. +6.0 or even mag. +6.5 from really dark locations.

In addition, the limiting magnitude will vary with altitude on the sky. Although you might be able to see a mag. +6.0 star at the zenith directly overhead, at 10˚ altitude the story will be completely different. Fortunately, Uranus is currently the UK’s best-placed planet, able to reach an altitude slightly over +50˚ when due south. This month it shines at mag. +5.7, tantalisingly ideal. Allow yourself 20 minutes in total darkness to become dark adapted. Once this is achieved you can locate the three brighter stars in Aries, Hamal (Alpha (a)), Sheratan (Beta (b)) and Mesarthim (Gamma (γ) Arietis). Next, look for the pentagonal shape that represents the head of Cetus; its brightest star, Menkar (Alpha (a) Ceti), is the one you’re after.

Uranus lies 60 per cent of the way along a line from Menkar towards Sheratan at the start of the month and then slips slightly southwest throughout November. Use our chart (below) to locate the useful guide stars that sit below the planet’s position.

The selected guide stars are useful because they present a range of magnitudes, which allow you to ‘approach’ the brightness of Uranus. Start with Mu (m) then Xi2 and Xi1 Ceti, all shining at mag. +4.3. Now go dimmer by moving on to 38 Arietis at mag. +5.2 , 31 Arietis at mag. +5.6, and finally mag. +5.7 Xi (ξ) Arietis before heading north to Uranus. Hopefully you can then add Uranus to the list of naked-eye planets you’ve seen.