During sunset on Saturday, three planets will form a bright cluster in the western sky known as the Dance of the Planets.

Venus, Jupiter and Mercury — the brightest planets visible on Earth — will move into a triangle only three degrees wide.

The triple conjunction of planets is fairly rare. The last time the three bright planets aligned in that formation was on May 9, 2011.

According to NASA, the best time to see the planetary dance is half an hour to an hour after the sun sets in the western sky.

The planets, NASA says, will be hugging the horizon and visible through the light of the sunset. They will even be visible in densely populated areas as urban light pollution is said not to deter their brilliance.

Once the triangle is formed, the dance will begin to disperse on Monday and will not be visible within the viewing field of ordinary binoculars on Tuesday.

The phenomenon won't happen again until Oct. 17, 2015.

Corrections

  • An earlier version of this story said that Jupiter, Venus and Mars will form a bright cluster in the western sky known as the Dance of the Planets. In fact, it will be Jupiter, Venus and Mercury.
    Sep 12, 2013 3:27 AM ET