(Reuters) - A "supermoon" rose above cities from Los Angeles to London on Saturday night, the first of three times this year the full moon will orbit nearer the earth and appear unusually large and bright.

The supermoon is technically known as a "perigee moon," and occurs when the moon is full as it reaches perigee, the point of its orbit closest to the earth, The National Aeronautics and Space Administration (NASA) said in a statement. It looks largest when it's closest to the horizon - an optical illusion.

"However, if it gets people out and looking at the night sky and maybe hooks them into astronomy, then it's a good thing," Geoff Chester of the US Naval Observatory, said on NASA's website.

A 2013 supermoon was 14 percent bigger and 30 percent more luminous than the average full moon of that year, NASA said.

Two additional supermoons are expected in 2014, one on Aug. 10 and another on Sept. 9, NASA said. August' s supermoon is expected to be the most remarkable of the year.

(Reporting by Laila Kearney; Editing by Larry King)