HONOLULU (AP) -- A team of Japanese astronomers using telescopes on Hawaii say they've seen the oldest galaxy, a discovery that's competing with other "earliest galaxy" claims. The Japanese team calculates its galaxy had formed by 12.91 billion years ago, and their research will be published in the Astrophysical Journal. The scientists with the National Astronomical Observatory of Japan used the Subaru and Keck telescopes on the summit of Mauna Kea. Richard Ellis of the California Institute of Technology, an influential expert in cosmology and galaxy formation, said the latest work as more convincing than some other galaxy discoveries. He said the Japanese claim is more "watertight," using methods that everyone can agree on. But he said it's not much of a change from a similar finding by the same team last year. Still, "it's the most distant bullet-proof one that everybody believes," Ellis said. In 2010, a French team using NASA's Hubble Space Telescope claimed to have discovered a galaxy from 13.1 billion years ago and last year a California team using Hubble said they saw a galaxy from 13.2 billion years ago. Both Hubble teams published findings in the journal Nature. However, the two Hubble teams have yet to confirm their findings with other methods, said Ellis. Also, a team of Arizona State University astronomers this month claimed to have found a galaxy from 13 billion years ago. They used a telescope in Chile. Current theory holds that the universe was born of an explosion, called the Big Bang, about 13.7 billion years ago. So astronomers using the most powerful telescopes available are peering deeper and deeper into the dawn of the universe.