A season of changes on Saturn

larger   These images of Saturn were taken between 1996 and 2000 by the Hubble Space Telescope

(CNN) -- Saturn has always made for great skywatching, even back in 1610 when Galileo first spied its rings. But a new sequence of pictures taken by the orbiting Hubble Space Telescope offers five times the viewing pleasure.

"They're the best observations we can do from the Earth," said Richard French, an astronomer with Wellesley College who helped compile the images.

Hubble took pictures of Saturn from several different angles between 1996 and 2000 showing the planet's rings opening up as it moved from autumn toward winter in its northern hemisphere.

The first image was taken soon after the autumnal equinox in Saturn's northern hemisphere. By the final image in the sequence, the tilt is nearing its extreme, or winter solstice.

GALLERY Click here to view the Saturn pictures     RESOURCES Saturn Facts     INTERACTIVE Cult 3D model of Hubble Space Telescope     MESSAGE BOARD Stargazing

Aside from being pretty, astronomers are studying the images to learn more about Saturn's rings -- how they were formed, and how long they might last.

"We can learn a lot about the rings from studying their color," French told CNN.com. The rings appear to be pale red, which researchers say could be due to the presence of organic material mixed with the water ice.

Hubble helps detect subtle variations in the color of the rings. Knowing the true color of the rings gives researchers a better handle on their origin, French said.

Saturn's rings are about 30 feet (10 meters) thick. The rings are made of chunks of dusty water, and they bump into each other as they orbit Saturn.

Even better pictures of Saturn may soon be in the offing. The Cassini/Huygens spacecraft, launched in 1997, is due to arrive in 2004 to land a probe on Titan, Saturn's largest moon, and to orbit Saturn for four years for a detailed study of the entire Saturn system.