Stargazers are in for a treat on Sunday as they could catch a glimpse of the so-called "supermoon" when the Moon appears bigger and brighter in the sky as it moves closer to Earth. It will appear about 7 per cent larger and 15 per cent brighter, although the difference is barely noticeable to the human eye, the BBC reported. December's full moon is traditionally known as the "cold moon". The full moon on Sunday night marks the first and only supermoon of 2017. According to NASA, a supermoon is a Moon that is full when it is also at or near its closest point in its orbit around Earth. Since the Moon's orbit is elliptical, one side (apogee) is about 50,000 km farther from Earth than the other (perigee). But within this orbit, further variations can be caused by the Earth's movements around the Sun. These mean that the perigee - the closest approach - and full moon are not always in sync. But the occasions when the perigee and full moon coincide have become known as supermoons. NASA has said that Sunday's supermoon is first in a series of three supermoons. The next two will appear on January 1 and 31, 2018. In 2016, the Moon made its closest approach to Earth since 1948. It won't be that close again until November 25, 2034.