Prime time for fall skies

I hope you enjoyed the 2007 version of the full harvest moon this past week. As nice as it was, it’s also great that we’re getting back our dark skies as the shrinking waning moon rises later and later after sunset. Autumn stargazing is now coming into prime time as October night skies wait for you and your family to get out and enjoy them.

As evening twilight fades, the bright planet Jupiter will pop out in the low southwestern sky, but not for long. In early October it sinks low in the sky by around 9 p.m., and by late October it’s lights-out for Jupiter by around 8 p.m. Through a small telescope, or any size telescope for that matter, Jupiter won’t exactly overwhelm as much as it did early this summer.

Not only is it much farther away (over half a billion miles), but it’s so low in the sky it will seem much fuzzier through your scope. That’s because the light has to travel through much more of Earth’s atmosphere than it did when it was higher in the sky.

You’ll also notice that Jupiter will take on a reddish hue, as all astronomical objects do when they get close to the horizon.

Speaking of red, the planet Mars rises around midnight in the east and is getting closer to the Earth. Mars will make its closest approach to Earth in late December. Stay tuned to this column in coming weeks for more on the Mars invasion in our skies.

In the rest of the western skies, what’s left of the summer constellations are still hanging in there. The “Summer Triangle” stars — Vega, Altair and Deneb — make it easy to find the constellations Lyra (the harp), Aquila (the eagle) and Cygnus (the swan).

Also in that same part of the sky is one of my favorite little constellations, Delphinus the Dolphin. Just look for a faint little diamond of four stars that outline the dolphin’s body and another faint star next to the diamond that marks the swimming mammal’s tail.

Because of Earth’s orbit around the sun, the nighttime side of the Earth faces a slightly different direction in space during the course of the year, determining which constellations we see and don’t see.

Over the course of this coming month you’ll notice that the stars in the western half of the sky start out lower and lower as evening begins. Eventually, by the end of October, some of the stars that were in the low western sky at the beginning of the month will already be below the western horizon before dark.

Meanwhile, in the eastern half of the evening October skies, the stars and constellations begin their nights higher and higher in the sky. The best one, in my opinion, is Pegasus (the winged horse), now flying higher in the east with the Andromeda Galaxy just above its wing.

In the low northeast, look for the bright star Capella leading in the constellation Auriga, one of the first wonderful constellations of winter. Time is marching on.

In the north are the ever-faithful northern constellations that are always above our horizon, even during the day when they lose out to daylight. The Big Dipper is nearly upright now in the low northern sky. The Big Dipper is not an “official” constellation but makes up the rear end and tail of the constellation Ursa Major, otherwise known as the Big Dipper.

By far, the brightest part of the Big Bear is the Big Dipper, and quite honestly the rest of the bear’s anatomy is too difficult to see because it’s just so low in the sky.

Just above the Big Dipper is the fainter Little Dipper, standing on its handle. The Little Dipper is otherwise known as Ursa Minor, the Little Bear. Another circumpolar constellation is Cassiopeia, which resembles a giant sideways W in the northeastern heavens. Just a little to the upper left of the queen is Cepheus, the king, looking like a faint upside down house with a steep roof.

Early next Sunday morning, Oct. 7, there will be a spectacular close conjunction in the low eastern sky about 5 or 6 a.m. The waning crescent moon will be right between the bright planets Venus and Saturn. Venus will be just to the upper right of the moon, with Saturn just to its lower left. Don’t miss it.

Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and author of the book “Washington Starwatch,” available at bookstores and at www.lynchandthestars.com.