A Super Harvest Moon will make a rare appearance in Toronto (and the rest of the Northern Hemisphere) tonight. It hasn't happened in almost 20 years, but as the sun dips down in the western sky tonight - the last day of summer - the moon will rise opposite it, creating what could be a spectacular show.

According to NASA, "For the first time in almost 20 years, northern autumn is beginning on the night of a full Moon. The coincidence sets the stage for a "Super Harvest Moon" and a must-see sky show to mark the change of seasons. The action begins at sunset on Sept 22nd, the last day of northern summer. As the sun sinks in the west, bringing the season to a close, the full Harvest Moon will rise in the east, heralding the start of fall. The two sources of light will mix together to create a kind of 360-degree, summer-autumn twilight glow that is only seen on rare occasions."

In Toronto, this 360-degree effect will take place at 7:17 p.m, which, if the skies are clear, is pretty much ideal timing.

Some instructions for best viewing (also from NASA): "Keep an eye on the Moon as it creeps above the eastern skyline. The golden orb may appear strangely inflated. This is the Moon illusion at work. For reasons not fully understood by astronomers or psychologists, a low-hanging Moon appears much wider than it really is. A Harvest Moon inflated by the moon illusion is simply gorgeous."

And, if you're otherwise occupied over the course of the sunset (and moonrise), at 11:09 p.m. - the exact moment of the autumnal equinox - Jupiter, the second brightest object in the sky, will reside directly beside the moon, which ain't too shabby either.

So, photographers grab those tripods and send your shots to the blogTO Flickr pool. If there are a bunch of good ones, I'll post them on the site tomorrow.

Photo by gardinergirl in the blogTO Flickr pool.