Next Friday night the moon comes close - very close. It'll be the nearest moon so far this century. And it happens the very night it's full.

This extraordinary state of affairs on December 12 will produce the highest tides of the year, called proxigean tides. If by chance there's a low-pressure storm at sea, or brisk onshore winds to raise the oceans a bit more, we'll see widespread coastal flooding, destructions of boardwalks and all the rest. The Hudson River will show dramatic tides too, well exceeding five feet Friday through Sunday. At the Saugerties Lighthouse, look for the peak high tide on Saturday just before 2 p.m. The path will be far underwater; you'd need to wade deeply to reach the Lighthouse.

During each low tide next Friday through Sunday, large expanses of beach will be exposed along the Long Island, New Jersey and Cape Cod shores; the waters will retreat further than we've seen in a long time. Clams, anyone?

The moon displays changeable behavior because its orbit is far from circular and swivels around us in a nine-year cycle like an egg-shaped hula hoop. Imagine: an orbit itself rotating!

Altogether, the moon's apparent size varies by more than ten percent. Making things even more interesting, the oval orbit's very shape keeps changing, becoming more eccentric when its long axis aligns with the sun. So each month the moon's closest point, or perigee, varies.

While each ordinary perigee occurs at random phases - crescent, half, anything - the moon's orbit distorts to its most extreme shape only when the moon is full and the sun is nearby and the orbit itself is properly aligned. This nexus happens once each decade or two. The last time was 1993. The next time all these conditions come together will be November 2016. A check of extremely accurate tables of the moon's motion shows that since the American Revolution, the very closest moon happened one January day in 1912 - and that was only about 100 miles nearer than it will be next Friday.

If you'd personally like to observe the rising of this largest of all full moons - the biggest moon you've probably ever seen - find a place with an unobstructed view of the northeast.

Moonrise is complete at 4:13 Friday afternoon, with the sun just about to set at the opposite horizon. The sun will therefore throw orange paint on all foreground earthly objects in front of the rising full moon. This is one of those Class A photography opportunities.

If the weather's not clear, you get a second chance, sort of: The next evening, Saturday, the moon will still look full and still look huge, but with moonrise at 5:28 - after the sun has already set. Thus, Saturday night's huge moonrise will happen in total blackness, robbing any chance of foreground photography but increasing the vividness and brilliance of the moonrise itself.

No camera? No problem. You still get to see one of those ancient sights that drove primitives and wolves berserk, but which may not even get a paragraph in contemporary newspapers: the largest moon of them all.