Observing

A guide to our updated interactive Almanac

If the current alignment of all the bright naked-eye planets — Mercury, Venus, Mars, Jupiter and Saturn — in the morning sky has prompted you to speculate where in the world might be the best place to view the spectacle, here’s a guide to using our upgraded interactive Almanac to help you find out.

News

Saturn’s rings: less than meets the eye?

You might think that, in the rings of Saturn, more opaque areas contain a greater concentration of material than places where the rings seem more transparent. But this intuition does not always apply, according to a recent study of the rings using data from NASA’s Cassini mission. The research also suggests that the planet’s brightest B ring could be a few hundred million years old instead of a few billion.

Observing

See the Moon’s ringed-planet rendezvous on 3-4 February

At 6am GMT on the mornings of 3 and 4 February, around the onset of astronomical twilight for the centre of the British Isles, the old waning crescent Moon brushes by ringed planet Saturn low to the south-southeast horizon. As a bonus for telescope users, the Moon occults globular cluster M9 shortly after 6am GMT on 4 February too.

Observing

See the Moon meet Mars in the pre-dawn of 1 February

As avid skywatchers will already know, all of the bright naked-eye planets are currently visible in the pre-dawn sky — the first time in eleven years that such an alignment has occurred. At 6am GMT on Monday, 1 February, the last quarter Moon in the constellation Libra lies just 2½ degrees from magnitude +0.8 planet Mars low in the south for UK observers.

Observing

See all five naked-eye planets gathered in the morning sky

All five of the bright naked-eye planets are observable in the pre-dawn sky from about the third week of January 2016, particularly if one lives south of the equator. But even from the UK, you can get to view the spectacle if you time it right — and the weather obliges! The last time that Mercury, Venus, Mars, Jupiter and Saturn appeared in the same sky was 11 years ago.

Picture This

Saturn’s moons Janus and Tethys

Janus and Tethys demonstrate the main difference between small moons and large ones; it’s all about their shape. Moons like Tethys are large enough that their own gravity is sufficient to overcome the material strength of the substances they are made of and mould them into spherical shapes, but small moons like Janus are not massive enough for their gravity to form them into a sphere.

Observing

See Venus and Saturn get close on the morning of 9 January

On the morning of Saturday, 9 January — just two days after their photogenic conjunction with an old crescent Moon — planets Venus and Saturn reach the denouement of their pre-dawn show with a spectacular close conjunction. To observe this spectacle you need an unobstructed view low to the southeast around 7am GMT (central British Isles).