Six planets will form a rare planetary alignment in the night sky on Jan. 21; here is everything you need to know about the 'planet parade' including how to watch it at night.

Although planets are technically always ‘aligned’ because they orbit the solar system on the same plane (the ecliptic), it’s rare to see four or five planets at once – and even more rare for them to appear in a line in the sky. The best time to see this row of planets is on Friday evening (January 31) at 6.45pm UK time, according to Starwatch.