On Tuesday night, at 10:06 p.m. EDT (0206 GMT), parts of the world where the moon is visible could see the astronomical opposite of a supermoon, the smallest full moon of 2011.

Astronomer Joe Rao, an instructor and guest lecturer at New York's Hayden Planetarium, ran a story on Space.com about the full moon "shrinking" to its smallest size this year.

"Less than 10 hours after the October full moon peaks, at 8 a.m. EDT (1200 GMT) on Wednesday, the moon will arrive at the apogee of its orbit (the farthest point from Earth each month), which in October is a distance of 252,546 miles. That's only 154 miles shy of the moon's absolute farthest point from Earth it can reach," Rao said.

"Last March, when the full moon was at perigee, some reported it as looking absolutely enormous as it emerged from above the eastern horizon. Not so on Tuesday, however, because the moon will very close to apogee, making this the smallest full moon of 2011," he added.

The moon will appear 12.3 per cent smaller than the "supermoon" of March.

Rao said casual skywatchers would think the moon is small and full for three nights - Monday to Wednesday, instead of just Tuesday - because the moon will be travelling relatively slower in its orbit while it is near its maximum distance from the Earth.

After seeing the smallest full moon this year, Rao said the new moon on Oct. 26 will coincide with perigree, meaning the moon will be near its closest point to the Earth.

"You won't be able to see the new moon because of its close proximity to the sun in the sky, but as was the case with the full moon in March, ocean tides will be more extreme for a few days around that time because of the lineup of the sun, Earth and moon," Rao noted.

Rao writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 in Westchester County, N.Y.