British astronaut Tim Peake will be spending this Christmas on board the International Space Station (ISS).
Far away from home he’ll share a special meal with all of his colleagues on board the station.
But on Christmas Eve, he will at least be able to look down on his home in the UK as the station passes over head.
If you want to head out to give Tim a wave (or to point out Santa’s sleigh to your children) spotting the ISS is really easy.
On 24 December 2015 the ISS will appear in the west at around 17:18 GMT, rising in the sky and then setting in the south around 10 minutes later.
The exact timing varies depending on where you are, so its best to look up the exact time it will be overhead beforehand.
There are several apps that will help you do this, such as ISS Detector Satellite Tracker and ISS?
For Android and ISS Spotter and ISS Finder for iOS.
These use your phone’s GPS to take your location and alert you to when the station will be visible.
Alternatively you can use the Heavens-Above website.
Input your location in to top right corner then head to the ISS section.
This will list all the passes the ISS will make over your location over the next 10 days, noting what time it will appear and set as well as what direction is best to look in.
If you click on the date you will also find a sky map with the path marked on.
A few minutes before the ISS is due to rise, head outside and look in the direction the table notes.
The ISS will be one of the brightest objects in the sky and will be moving about the speed of an aeroplane, so it should be fairly obvious.
The light from the ISS is reasonably steady, but in the evenings it sometimes appears a little dim at first and then gradually brightens, while in the morning the opposite is true.
This is caused by the station moving into and out of the Earth’s shadow, as the light is caused from the Sun’s rays bouncing of its reflective surfaces rather than being produced by the station itself.
Just remember to give Tim a wave when you see it overhead.
