SkyWatch
October 2002
By Steve Stefanik
As the sun sets this October, the "birds" of summer Aquila the eagle and Cygnus the swan are directly overhead, winging their way southwestward, another sure sign that winter is on its way. They are giving way to the "great square" of the constellation Pegasus, the rider-less mythological winged horse, which is "flying" high in the southeastern sky during this season of ghosts and goblins. The "teapot" asterism in the constellation Sagittarius is low on the southwestern horizon and is tipped as if to pour us a cup of tea to warm us during the chilly nights of autumn.
You may be able to spot the last vestiges of the planet Venus to the right and west of Sagittarius only 10 degrees above the horizon. You shouldn’t have difficulty seeing this –4.5 magnitude marvel if you have a clear view of the horizon. It sets about an hour after the sun goes down. Venus sets approximately two or three minutes earlier each evening until it disappears with the sun on October 23rd.
Although the October night sky appears to become "planet-less" after Venus sets, there are actually two other planets that are well positioned in the southern sky although you will need binoculars or a telescope to spot them. Both the planets Neptune and Uranus are currently amidst the stars of the constellation Capricornus. Magnitude +7.9 Neptune is in the western end of the constellation near a +7.3 star, which makes it appear as if they are a pair of binary stars but through a telescope you will see the bluish-gray disk of the planet next to a scintillating pulsating star. Uranus is much easier to find. It lies in eastern Capricorn near a bright +2.8 magnitude star. If you live away from city lights you may be able to spot this greenish-blue planet with just your eyes but through binoculars or a telescope it is unmistakable. You may even be able to spot several of its larger moons orbiting it.
If you’re still out and about, just before mid-night the planet Saturn rises between the constellations Taurus and Gemini in the east. It actually spends the month of October in part of Orion the hunter and through binoculars you can locate it about 4 degrees southwest of M35 an open star cluster. Through a telescope you’ll be able to see its rings, which are tipped southward about as much as they ever get. You may even be able to make out the gaps in its ring system and possibly its largest moon Titan.
The planet Jupiter rises in the east after mid-night. The brilliant –2.0 magnitude gas giant is hard to miss but if you aren’t sure it lies just to the east of M44 the "Beehive Cluster" of stars in the constellation Cancer the crab. Through a telescope you’ll be treated to a dynamic view of alternating light and dark bands, moving cloud patterns, a giant red spot, white festoons, and four frolicking moons.
If you’re just getting up for work or school the planets Mars and Mercury are also just rising in the murky morning twilight low on the eastern horizon in the constellation Virgo. Mars is the dimmer of the pair at +1.8 magnitude. Mercury is also dim in the beginning of the month but brightens considerably from +3.6 to –0.1 during the middle two weeks of the month. Between October 8th and 10th , Mercury gets closer and closer to Mars until they are within 2.8 degrees of each other. Mercury reaches greatest elongation from the sun on the 13th when it begins to pull away from Mars and sets below the horizon once again by month’s end.