Amateur astronomers will tonight get the chance to see the International Space Station (ISS) as it flies over Irish skies.
The €100 billion ISS will be joined by a Nasa shuttle on an 11-day mission to attach a giant frame to hold the station's 80-metre solar panels.
These extensions will make the space station the largest and brightest object ever to fly in Earth's orbit.
"It is an incredibly spectacular sight to the naked eye, outshining every star in the sky," Chairman of Astronomy Ireland David Moore said.
"But when the shuttle chases ISS across the sky it is an incredible sight with two 'stars' blazing across Irish skies - everyone should see this, it's history in the making, and Ireland just happens to be in the right place at the right time".
The ISS is the most expensive piece of space hardware ever, representing a collaborative effort of nearly 20 countries, including Ireland.
Since its launch in 2000, the 200-tonne space station, 73 metres wide, has travelled over two billion kilometres in 48,000 orbits. For a couple of minutes every night it outshines every star and planet in the night sky.
To get exact times of the flyovers, which will take place all weekend, Astronomy Ireland has set up a special newsline - 1550 111 442.