SUNRISE and sunset on a planet far, far away would be twice as spectacular as here on Earth, astronomers say.

NASA today will announce the discovery of a planet with two suns, like Tatooine in the movie Star Wars.

The newly-found planet, Kepler-16b, is named after the NASA Kepler space telescope, which is on a mission to find Earth-sized planets capable of supporting life.

While this planet is too cold, between -100C and -70C, scientists say it is a "treasure" worthy of further investigation.

"Kepler-16b is the first confirmed, unambiguous example of a circumbinary planet - a planet orbiting not one, but two stars," Josh Carter, of the Harvard-Smithsonian Center for Astrophysics, says. "Again, we're finding our solar system is only one example of the variety of planetary systems nature can create."

Commenting on the research, Dr Simon O'Toole from the Australian Astronomical Observatory says it's a "very, very cool" discovery.

"If you could stand on the surface of the gas planet at dawn, the sight would be stunning," he said.

"You would see one star rise and then the other star.

"Every day would be slightly different ... and the sunset - like in the first Star Wars movie, when Luke Skywalker is looking out over the sunset and there are two stars, that is the kind of thing that you would see - would be twice as spectacular as it is here on Earth."

The paper published today in the journal Science describes a planet comparable with Saturn in mass and size. It is on a nearly circular 229-day orbit around its two parent stars.

The stars are 20 and 69 per cent as massive as the Sun and have a 41-day orbit.

Kepler is a 0.95m telescope that monitors the optical brightness of about 155,000 stars in the constellations Cygnus and Lyra.