That's why the full moon is special tonight.

The moon is offering astronomy enthusiasts a special spectacle on Monday evening. According to NASA, Earth's satellite will appear at full power in the Berlin night sky at around 8:26 p.m. Its appearance as a full moon is considered rare by experts: it is a seasonal blue moon. But that's not the only special feature: It appears as a supermoon this year.

There are actually twelve full moons in each calendar year. But since the lunar cycle lasts 29.5 days, an extra full moon occurs every three to four years. August 19 is one of these—and the third of four summer days. Because blue moons don’t happen very often, English even has the phrase “once in a blue moon,” used to describe very rare occurrences. The moon will not shine blue in August, and it’s more common for the moon to appear red due to its position relative to Earth.

The full moon on August 19 is a supermoon.

In addition, the moon will appear on Monday evening according to NASA It will be a supermoon because it is so close to Earth. The term “supermoon” was coined by astrologer Richard Noll in 1979 and refers to either a new or full moon that occurs when the moon reaches 90 percent of its closest approach to Earth. It is usually about 230,000 miles (385,000 kilometers) from our planet. So the moon is likely to appear unusually large in the sky, although not quite as impressive as the upcoming supermoons in September and October.

This year, the August full moon also coincides with the Perseid meteor shower. Although it peaked last week, many of the shooting stars can still be seen at night in the light of the large supermoon. By the way, in case you’re wondering why the bright spot is so close to the moon: Saturn can be seen especially close to the moon this week.