One of the biggest planetary storms seen in the solar system has dramatically blown up on Saturn. It is so big and so bright that it can be seen in backyard telescopes.

The tempest raging in the cloudtops of the ringed planet’s northern hemisphere is half the size of the Earth. Thousands of miles long, it is also being closely monitored by NASA’s spaceprobe Cassini which is currently in orbit around Saturn studying the 74,500-mile wide gas giant and its family of moons.

The spacecraft’s instruments are picking up strong bursts of radio static and its cameras picturing violent lightning flashes. You can listen to a similar storm caught by Cassini here.

Amateur astronomer Anthony Wesley captured the storm through his 16-inch reflecting telescope from Murrumbateman, in New South Wales, Australia.

He told Skymania: “This is a very rare and impressive display. Violent convective lightning storms on this scale happen maybe every 10 to 20 years on Saturn. The Cassini spacecraft is picking up a very large number of lightning strikes spread through the storm system showing how active it is, spread out over approximately 50,000 km (30,000 miles). It makes an impressive sight through any telescope of 4-inch or larger aperture.”

Saturn is currently in Virgo in the morning sky, rising a few hours before the Sun. The planet, which is big enough to contain more than 760 Earths, has some of the fastest winds in the solar system, blowing at up to 1,120 mph. A previous giant storm which erupted in 1933 was discovered as a bright white spot by the British comic Will Hay, famous for his roles in films such as Oh, Mr Porter!

A hurricane that raged in 2007 and 2008 in a zone on Saturn that NASA calls Storm Alley produced lightning bolts 10,000 times more powerful than on Earth. Amateur astronomers helped monitor that storm in Saturn’s southern hemisphere. Another blew up in 2009.

Saturn’s yellowish atmosphere is mainly made up of a mix of hydrogen and helium and its rapid rotation gives it a day just 10.5 hours long. Monster tempests also blow at the giant planet’s poles. That at the north pole is peculiar for being shaped like a six-sided hexagon.