Five months after it was launched on a mission to find earth-like planets, the Kepler space telescope has sent back to earth high-precision images of a planet some 1,000 light years away, according to Nasa.

But the real excitement at Nasa was over how well Kepler was working, and the promise it holds for the future.

With Kepler only in the calibration phase, the telescope, which was launched in March on a mission to find earth-like planets in the galaxy, sent back to Earth highly precise images of a planet with the unromantic name of HAT-P-7-B.

The images of the so-called hot Jupiter planet located about 1,000 light years (around 9.5 quadrillion kilometres) from earth were "the first time anyone has seen light from this planet," said William Borucki, the principal science investigator for the Kepler mission and lead author of a report that was published on Friday in Science.

But while the scientists were enthusiastic about Kepler's discovery of optical light from HAT-P-7-B - Carnegie Institution astrophysicist Alan Boss called it "stunning indeed" - they were even more excited by the fact that Kepler was working, and working well.

"The real headline is Kepler works," said Mr Boss.

"The implication from this is that Kepler has the ability to detect the transit of an earth-size planet passing in front of a sun-type star producing a very tiny dimming.

"Kepler was launched not just to find exo-planets but its prime mission is to count how many earths there are around sun-like stars in our region of the galaxy. We now know Kepler can do it," he said.

The data were gathered by Kepler during the first 10 days of data-gathering, boding well for the next few years that the telescope will spend trained on the same spot in space, taking in about 100,000 stars around the Cygnus and Lyra constellations of the Milky Way.

"The observation demonstrates the extremely high precision of the measurements made by the telescope, even before its calibration and data analysis software were finished," Nasa said in a statement.

At a cost of nearly $600 million (€418 million), Kepler is the National Aeronautics and Space Administration's first mission in search of earth-like planets orbiting suns similar to ours.

It is equipped with the largest camera ever launched into space - a 95-megapixel array of charge-coupled devices.

Nasa scientists expect to be able to say by 2012 if there are "lots of earths in our galaxy or we are alone," thanks to data sent to earth by Kepler.