will we see this in Ireland?
The most stunning night-sky display for years takes place this evening.
Five planets will be seen strung out in a near-perfect line in the rarest of astronomical phenomena. Nicknamed "the fab five" by Nasa, Mercury, Venus, Mars, Jupiter and Saturn will be visible in the west an hour after sunset.
"They're all on the same side of the sun and stretched across the sky, and that's what is kind of pretty," said Myles Standish, an astronomer at Nasa's Jet Propulsion Laboratory in Pasadena, California.
Experts have warned that Londoners could encounter some difficulty in spotting the planets because of the light pollution that can engulf the capital.
Andy Hayward of the National Space Centre in Leicester said: "In central London going to a park will be your best bet, as there is just too much light around otherwise.
"But with the naked eye, if you find a large open space to block out streetlights, you should be able to spot everything.
"If you have a telescope, it's also an amazing night to be out looking because as well as the five planets in an almost perfect straight line, there will be two comets visible. It should be pretty spectacular." Nasa says today's line-up may offer the best night-time planetary views until 2036.
Mercury, the closest planet to the Sun, will be the closest to the horizon, the most difficult to spot, and the quickest of the five to disappear after the sun sets. Above Mercury will be Venus, the brightest object in the night sky after the moon.
Next will come reddish-hued Mars, followed by Saturn, which can be seen almost directly overhead. Tracing the line beyond Saturn will find Jupiter, the
solar system's largest planet.
All five worlds will be visible - though not in such a straight line - in April.
Their orbits take them to the same side of the sun every few years, but conditions have to be just right for them all to be visible.