By some measures, Sunday night's full moon is the only supermoon of 2017. Some people call the second full Moon in a month a Blue Moon, that makes it a super "blue Moon.' Blue Moons happen every two and a half years, on average". When the moon is full during the portion of its orbit that brings it closest to Earth, Space.com reports, a supermoon occurs. The next time the moon will come that close to the Earth will be on November 25, 2034. The moon's orbit around our planet is tilted so it usually falls above or below the shadow of the earth.
It will shine up to 30 per cent brighter, not only because it's close to Earth, but also because Earth will be nearing its closest to the sun in early January. That means during each month the moon is sometimes passing closer to the earth than others. But that doesn't mean this weekend's supermoon won't be handsome - expect a full moon at least 7% bigger and 16% brighter than usual.
The only supermoon of the year is slated for December 3, 2017, at precisely 15:47 UTC, according to EarthSky.org.
While the moon is undoubtedly both bigger and brighter than usual, our eyes tend to trick us into seeing the moon as larger than it truly is.
This weekend, sky-watchers can look forward to a phenomenon that hasn't yet graced the skies this year: a supermoon. Even more so if it's a supermoon.
This optical illusion also occurs when watching the supermoon immediately after sunset (or before sunrise).
A supermoon occurs when there is a full moon at or near the point where the moon reaches perigee. On the three dates marked, step out into the moonset or moonrise and look up for a trilogy of sky watching treats!