October skies

As the days get shorter and colder, the night sky offers a refuge of things bright and beautiful. And in October, we get a few bonuses as the seasons turn - at least for stargazers willing to lose a little sleep.

After midnight, the glittering constellations of Orion the Hunter and Gemini are rising in the east, while the Summer Triangle of the stars Altair, Deneb and Vega are hanging on for dear life in the west.

The cusp of the seasons is a good time to compare the brightness of stars that make up the constellations.

Orion's appearance is always a mixed blessing - if the Hunter is coming up, the temperatures are going down. But on the bright side, excuse the pun, this is an extraordinary group of stars.

That's obvious when you turn from Orion to look overhead or to the west in late-night October. Most constellations have only one or two bright stars: you usually have to work to connect the dots with the dimmer remainder.

I can remember risking a neck strain trying to make out the six stars of the Northern Cross, officially known as Cygnus the Swan. This constellation straddles the Milky Way with its brightest, or alpha, star Deneb at the top of the cross.

Cygnus is now a familiar sight after years of exploring its treasures, such as the gold and blue double-star Albireo at the foot of the cross.

Then there's Orion. The brightness, or magnitude, of many of its stars are in the 0 to 2 range. That might not sound all that impressive. But under the magnitude system - which was created 2,000 years ago by the Greek astronomer Hipparchus and tuned up by the English astronomer Norman Pogson in the 1800s - the lower the number, the brighter the star.

In fact, really bright objects such as Venus, the full Moon and, of course, the Sun, go into the negative at -4, -13 and -26 magnitudes respectively.

The other constellation that stands out as we scan the late-night October sky is Ursa Major or Great Bear, which prowls the northern regions.

Ursa Major boasts a number of second- and third-magnitude stars, which come together in the famous Big Dipper group.

So for the dedicated night owls out there, it's a rewarding time of year.

But there's lots to see at a more civilized hour. For example, the royal couple of autumn holds court in the northeast. Queen Cassiopeia (cass-ee-oh-PEE-uh) and the king Cepheus (SEE-fee-us) reign in the eastern wing of the Milky Way, which is studded with star clusters.

The big draw in this region is the Double Cluster, which technically is in the constellation Perseus. However, I find that two stars in Cassiopeia act as a handy pointer to this beautiful pair of star clusters, located about 7,500 light-years away from Earth.

In dark skies with the naked eye, the Double Cluster looks like a couple of dim, fuzzy stars. But through binoculars, the clusters break down into glittering splashes of stars that easily fit into one binocular field.

To find them, locate the slanted W of Cassiopeia. The central star in the W and the dimmer star below and to the left point toward Perseus. The Double Cluster lies in this direction about halfway to Perseus. (See star chart.)

Another nearby cluster, called M52, boasts more than 100 stars. It can be found between Cassiopeia (its top two stars point toward the cluster) and the house-shaped and relatively dim constellation of Cepheus.

Turning to the south, the skies in this direction look pretty desolate in late-evening October, after Sagittarius and Scorpius dip below the horizon. Shining a little light into the gloom is the first-magnitude star Fomalhaut (FO-mal-owt) which reaches its highest point in the south this month. At a distance of 22 light-years, it's one of our closer neighbours in space.

If you like stuff that moves, two meteor showers are coming up. The Orionids (Oct.21/22 ) and Northern Taurids (Nov. 11/ 12) aren't big events, producing about 10 to 25 meteors an hour. But both showers have been known to feature bright meteors and even fireballs.

For the Orionids, the first-quarter moon will wash out some meteors by the time it sets at 1:28 a.m. on Oct. 22. But the hardcore meteor watchers will still be up -  the peak of the show occurs from one to two hours before dawn.