Sadly this is the last full week of summer with astronomical autumn getting started next Sunday afternoon.

Set your clocks or watches, if you really want to for 4:44 p.m., the moment of autumnal equinox.

That's when the sun slips below the celestial equator which is a projection in the sky of the Earth's terrestrial equator.

From day to day and week to week until Dec. 21, the sun's arc across the sky will become lower and lower as well as shorter and shorter as we dive toward winter.

In the meantime, this week will be lit up nearly 24 hours with sunlight by day and moonlight by night.

That's because we have more or less a full moon all this week. The exact night of the full moon this coming week is Thursday night/Friday morning, and since the full moon this week is close to the date of Autumnal equinox it's the annual harvest full moon.

It got its name because it lights up the night sky right around harvest time.

Now any full moon will rise around sunset and set around sunrise but astronomically what makes the harvest moon so special is that is rises only about 20 minutes later each night instead of the usual 45 to 50 minutes so there isn't as much of gap between the time the sun goes down and the moon rises.

Why does this happen? It's a complicated story for another column, but it's a case of unique celestial mechanics at work.

This week the ecliptic, which is the plane of Earth's orbit around the sun, is at a very close angle to the horizon in the evening.

Before headlights were an option on John Deere tractors, farmers could take advantage of the harvest moon with its pale light to extend their time in the field.

It's not easy though. Eagle eyes, strong coffee, and determination were also needed for nocturnal farming in the dimmer moonlight. You could easily miss spots.

Even now with headlights on tractors the full harvest moon is still a friend to the farmer. However, that inconsiderate neighbor of yours can mow his lawn by the light of the silvery moon and drive you up the wall.

What I'd like to do is follow the harvest moon across the sky from the eastern to the western horizon through the course of a night and catch some of the other highlights in the night sky.

Admittedly, the fainter celestial treasures will be “moon washed” and tough to see.

When that full harvest moon is on the rise in the evening twilight it's a sight to behold. That huge orange orb rising can be breathtaking. No words can adequately describe it.

Like any full moon on the rise, it sports an orange hue of varying degrees, depending on the clarity of Earth's atmosphere. That's because the moon's light has to plow through more of Earth's atmosphere when it's close to the horizon, and that scatters away all but the orange and red components of the moonlight.

When the moon gets higher, its light doesn't have to fight its way through as much atmosphere and it turns white. The moon also seems a lot larger when it's rising or setting. Believe it or not, that's just an optical illusion. The same thing happens with the sun and even constellations when they're close to the horizon.

While you're getting moonstruck watching the moon rising in the east, take a half turn and you'll see a couple of planets in a wonderful celestial hug in the west-southwest sky. They're Venus and Saturn.

Venus looks like a super bright star with Saturn, not nearly as bright, just to the upper right.

Through even a small telescope you should be able to make out the ring system of Saturn, although it'll be really fuzzy since Saturn is so close to the horizon.

Saturn is way, way larger than Venus, but is about 10 times farther away. Venus is only about 92 million miles away while Saturn's nearly a billion miles distant.

If you're under the magical moonlight in the midnight hour, the moon will be beaming in the southern sky. With the naked eye you can easily see the dark areas called maria. They are the volcanic plains of the moon.

It's in the darker maria that you can see “the man on moon.” The white areas are the highlands and mountains. Craters completely litter the lunar surface and around some of the bigger ones you can see the radial patterns of rays.

If you check out our lunar neighbor with a telescope, I would highly advise looking though sunglasses. It's so bright you could earn yourself a big time headache and make yourself a little looney!

While you're enjoying the midnight moon, look in the low eastern sky for a cute little cluster of stars.

That's the Pleiades, otherwise known as the “Seven Little Sisters.” Astronomically it's a cluster of young stars a little more than 400 light years away, all born together about 100 million years ago.

By the way, just one light year is almost six trillion miles. It's a not a weekend trip to the Pleiades.

If you're pulling an all nighter or you're a super early riser, you'll see the harvest moon heading toward the western horizon and starting to turn orange again.

Meanwhile the eastern half of the sky will be lit up like a Christmas tree with so many bright stars and constellations. I call that part of the sky “Orion and his Gang.”

The marquee constellation is Orion the Hunter with three bright stars in a row that make up his belt.

Orion's gang makes up the bulk of the wonderful winter constellations that we'll see in the evening sky in January and February, but early risers get a sneak preview.

As a bonus, the brightest star you can see in the east is actually the planet Jupiter making a visit this year to Orion and his gang.

Enjoy dancing in the full moonlight this week even it costs you some sleep.

Catch up on that next weekend!