It's not every day you get to name a celestial body, is it? Luckily for us today just happens to be one of those days.

The International Astronomical Union (IAU), the professional body responsible for conferring official names on astronomical objects (among other things) has just opened up the final round of its NameExoWorlds contest. The initiative gives the public its first ever official chance to name planets and stars outside our Solar System, which is a pretty big deal when you think about it.

The names the public gets to vote on come from 247 proposals submitted by astronomy clubs and non-profit organisations around the world, with nominations from 45 countries in total. All up there are 20 planetary systems waiting to be named, comprising 15 stars and 32 exoplanets. And you thought naming your pet cactus was tough!

There's a bizarre range of suggested monikers to vote on, pulling in names from myths and legends, pop culture references like characters from science fiction novels, and even Japanese foodstuffs. There's a definite geeky theme throughout the selections on offer, and that's perfectly understandable. (Clearly you don't get your astronomy club affiliated with the IAU without being in possession of some serious geek credentials.)

Taking part in the voting process is simple. Information about the nameable systems including a full list of the ExoWorlds is here, and instructions on how to vote – which is entirely free and doesn't require any registration – can be found here. There are also some pretty cool artistic renderings of the systems on offer to help you get your muse on.

If the whole naming planets thing sounds a little familiar to you, that's because this isn't the first time somebody's tried this. A few years back a company called Uwingu rolled out a commercial naming rights scheme for planets. This was promptly met with a sharp rebuke from the IAU, which pulled rank by announcing that it wished "to inform the public that such schemes have no bearing on the official naming process."

Uwingu's efforts did however help to encourage the IAU to bring the public more on board with planetary naming, although its first attempt to do so – in which the public voted to name one of Pluto's moons 'Vulcan' – had to be disqualified on the grounds of a rather curious technicality. Unfortunately, another planet had already been given that name, and even though that planet was found to not exist… the name stuck. That's some spacey logic for you right there!

But anyway this time it's the real deal, representing the closest thing there is to an authoritative and hopefully watertight naming process for exoplanets (at least from the cosmically narrow perspective of our little corner of the galaxy). So don't delay. Voting is only open until midnight on 31 October 2015. Get cracking.