October 2005

by Deane Morrison

After long months of waiting, we finally get to see Mars in its full glory. Rising just ahead of the Pleiades, the Red Planet glows a soft pumpkin color during October. On the 1st, Mars appears by 9 p.m., but by the end of the month its ruddy disk comes up around sunset. Mars comes up earlier because Earth overtaking it in the orbital race; during October the distance between our two planets shrinks from 49 million to 43 million miles. Earth comes closest to Mars on the evening of the 29th and passes it on Nov. 3. We'll be farther away than we were in August 2003, the date of the last close pass, but Mars will appear about twice as high in the sky as it was then.

The full hunter's moon arrives at 7:13 a.m. CDT on the 17th. The moon will undergo an eclipse that morning, but no more than one-thirtieth of its surface will dip into Earth's umbra, or dark inner shadow. The eclipse begins at 4:51 a.m., when the moon first touches Earth's penumbra, or light outer shadow. At 6:34 a.m., the umbra starts to spread over the moon's nether section, and the moon sinks into deepest shadow - such as it is - at 7:03 a.m. The moon sets at 7:39 a.m., having just quit the umbra but still shaded by the penumbra.

The moon will wane almost completely away by Halloween, so the little trick-or-treaters will have no spooky crescent hanging over them as they take to the streets. Halloween was called Samhain (rhymes with COW-en) by the ancient Celts, and it is one of the four cross-quarter days that fall midway between an equinox and a solstice. It was the start of the dark half of the year, when evil spirits came out of a six-month exile and wreaked havoc. Pure fantasy? No; the Celtic legends were based on real woes like the spoilage of freeze-damaged crops and the onset of respiratory diseases. Today we know that those evil spirits are really microbes such as bacteria, molds and viruses, some of which hide in bird or mammalian hosts during the warm months and infect people when it gets cold.

Planet lovers will have little in the evening sky besides Mars, since Venus spends the month low in the western twilight and Jupiter disappears behind the sun on the 22nd. Mercury makes a brief foray into the evening twilight near the end of October, but it will be very difficult to find.

The morning sky offers Saturn, which rises after midnight and appears fairly high in the southeast near dawn. The ringed planet is near the Beehive star cluster, an ornament in the otherwise unremarkable constellation Cancer. Look for Saturn east of the Gemini twins. Another way to find the planet is to look below the waning moon the morning of the 25th and above the moon on the 26th.

October is the best time to spot several dim water constellations. Piscis Austrinus, the southern fish, swims in the south, marked by the bright star Fomalhaut. Above Fomalhaut, from southwest to northeast, are Capricornus, Aquarius and the Circlet of Pisces. The Circlet should be easy because it's right below the Great Square of Pegasus. Between Pegasus and the Summer Triangle of bright stars, you may find little Delphinus, the dolphin, leaping toward the celestial horse.

Standard time returns at 2 a.m. on the 30th. Clocks should be set back an hour. The changeover gives us an extra hour of morning daylight but makes night fall an hour sooner. That's not good news for late sleepers, but for star watchers it sure comes in handy.