October 2009 (update 3)
Skywatchers’ Guide for October 2009
HIGHLIGHTS: The planet Jupiter dominates the evening sky and is the brightest star like object visible until it sets in the morning hours. Even more brilliant is Venus, but it’s low in the morning sky. Venus, Saturn and Mercury group just above the eastern dawn horizon during the first half of the month and the Moon forms a lopsided triangle with Venus and Saturn on October 16. The Full Harvest Moon rises on the evening of October 3, setting on the morning of October 4. The peak of the Orionid Meteor Shower should occur on October 21, and this several night long shower is unhindered by moonlight.
PLANETS
 The evening sky in October around 75 minutes after sunset, facing southwest. This sky chart is most useful for the southern United States and northern Mexico.  The Moon and Mars, high in the eastern morning sky on October 11-12, at around 5:15 a.m. This sky chart is most useful for the entire United States, southern Canada and northern Mexico.  The planets Venus. Saturn and Mercury in the eastern sky on October 1, 7 and 12 at around 5:30 a.m. This sky chart is most useful for the entire United States, southern Canada and northern Mexico. |
Bright Jupiter dominates the southern sky in October for a few hours after sunset, especially during the first half of the month. Gas giant Jupiter appears one hour after sunset as a very bright, almost brilliant white star-like object, high above the southern horizon in early October evenings, but moving toward the southwestern horizon by the last week of October. On October 1 Jupiter is still bright (brighter than magnitude -2.3) and large in a telescope (around 40 arc seconds wide), though by October 30 has faded a little from its brightest and largest back in August. October continues to be a very good time to view the giant planet in the evening hours. Look for bright, whitish Jupiter far east (or roughly far ‘left’) of the Teapot of Sagittarius: It’s the brightest star like object well up in the evening sky in October. Jupiter is highest and due south in bright evening twilight in early and middle October (at around 40 degrees in altitude for much of the Desert Southwest). Look for the waxing gibbous Moon to slide below (and west) of Jupiter in the southern sky on Monday evening, October 26.
When looking at Jupiter in a telescope to view its cloud belts and festoons, the sharpest views should be just after sunset in evening twilight, when at or near its highest in the twilight sky this month. As with any planet viewing is dependent on atmospheric stability and conditions, and of course, the quality and size of the telescope used. However to view its moons, a good pair of binoculars is all that’s needed. Jupiter sets in the west-southwest around 2:30 a.m on October 1, around 1:30 a.m on October 15 and around 12:30 a.m. in late October.
The brilliant planet Venus is losing altitude this month and nearing the eastern dawn horizon. As it does so it groups with Saturn on October 12-13. At the start of October Venus lies about 12 degrees above the eastern horizon, 1 hour before sunrise, but sinks to 4 degrees in altitude by October 27. Look for the 28 day old waning crescent Moon to form a lopsided triangle with Venus and Saturn on October 16.
Mars, now near 0.5 magnitude in brightness, lies over 50 degrees to the west of Venus (in Cancer, the Crab) on October 1. The two continue to drift farther apart each day so that Mars is overhead by the end of October with Venus far away and just above the eastern horizon. Mars is still a long ways off from Earth (hence its faintness compared to Venus) and, although much brighter now, still continues to be an unremarkable object in a telescope (only 7.8 arc seconds wide). Look for the last quarter Moon nearest Mars in our sky on the morning of October 11.
Saturn emerges from the glare of the Sun and rises earlier above the eastern horizon each morning this October. In early October look for Saturn in the morning twilight one hour before sunrise: It will be barely above the eastern horizon as a slightly brighter than 1st magnitude star-like object. By middle October Saturn is over 10 degrees above the eastern horizon, one hour before sunrise, but by late October climbs to over 23 degrees in altitude at that time. Saturn is found below the constellation Leo the Lion. Look for Venus to group with Saturn on October 12-13 and the 28 day old waning crescent Moon to form a lopsided triangle with both Venus and Saturn on October 16.
The elusive planet Mercury is found in the dawn twilight, close to the eastern horizon during the first half of the month. It is brightest and best visible starting about one hour before sunrise from October 1-10, when it is brightest (at almost -0.7 magnitude on Oct. 10) and still 5 degrees above the eastern horizon. Look for Mercury to group with Saturn in the dawn twilight on October 7-8.
Visitors to Flandrau’s 16-inch telescope should note that Jupiter is visible in the telescope during public hours. Other celestial objects will be shown in the telescope, weather permitting. Although Flandrau’s main exhibit hall and planetarium are now closed to the general public due to state budget cuts, school groups can arrange for planetarium and Mineral Museum field trips. The Mineral Museum is normally open Friday and Saturdays to the public from 9:00 a.m. to 5:00 p.m. (and by appointment). The Flandrau Observatory remains open for viewing during public hours from 7-10 p.m., weather permitting, Wednesday through Saturday nights (excluding select holidays). Finally, remember that in spotting planets there is a general rule: ’stars twinkle, planets don’t’. This is because stars are point sources of light; therefore starlight is easily disturbed and shifted by air currents in the Earth’s atmosphere. However when looking at Mercury or Mars this month, note that they appear to twinkle somewhat; however, this twinkling is of a slower nature than that of the bright stars.
OCTOBER EVENING STARS
 This chart shows the sky overhead around the Summer Triangle for much of the night in October, from around 9:30 p.m. - 2:30 a.m. in early October, from 8:30 p.m. - 1:30 a.m. in mid October, and from 7:30 p.m - 12:30 a.m. in late October.  This sky chart shows much of the early night sky in October that can be seen overhead before 9 p.m. |
Overhead anywhere in the U.S., at the end of evening twilight, stargazers can find the bright stars of the widely spaced triangle Summer Triangle: Vega, Deneb, and Altair. In October the Summer Triangle slowly loses altitude and sets in the western sky after midnight. Vega, Altair, and Deneb are each the brightest stars of three constellations that make up the Summer Triangle. Vega is the brightest star in the small constellation of Lyra, the Lyre (a small ancient harp). Vega, one of the closer stars to Earth (only 25 light years away), was the Pole Star (our North Star) some 12,000 years ago, and will again be the North Star in 12,000 A.D. when Earth’s cyclical wobbling motion brings in near the pole once more. Deneb is the tail of Cygnus the Swan, but also marks the bottom of the cross-shaped pattern whose other name is the Northern Cross. Deneb is a huge supergiant star over 1,600 light years from Earth. Aquila, the Eagle is the home of the bright star Altair, the first star of the three in the triangle to set late at night and the closest of the three to Earth at only 16 light years distant. Aquila looks more like a diamond or kite than an Eagle. Aquila and Cygnus (or the Northern Cross) mark some of the brightest areas of the northern Milky Way, which is prominent in dark skies on Moonless October nights.
Taking center stage in October is the Great Square of Pegasus. Find the Great Square quite a ways up from Fomalhaut, the bright star marking the Southern Fish, which lies somewhat low in the south. Alpheratz, the eastern corner star of the “Great Square” of Pegasus, is also the head of Andromeda, the Chained Lady or Princess. In Andromeda, is the “Great Andromeda Galaxy”, M31, which can be viewed as a fuzzy spot in binoculars. Rising in the eastern sky (and far from M31) is the Seven Sisters (or Pleiades) star cluster, a wonderful sight in binoculars.
The Orionid Meteor Shower
 The sky chart shows Orionid Meteor Shower in the southeastern sky. |
Night owls will get to an excellent view of the Orionid Meteors barring cloudy weather this year. The shower peaks on the evenings of October 20, 21 and 22, and starts around 11 p.m (but is better after midnight). The best night to view the shower should be Tuesday night into Wednesday morning October 20-21. The waxing crescent Moon won’t hinder viewing at all this year. Meteor watchers, warmly dressed and with ample supplies of hot chocolate, should seek out a dark sky several miles away from city lights and scan the sky from the southeast to northeast and overhead. The name of the shower results from tracing meteor paths back to the constellation they appear to come from, in this case the constellation Orion. Viewers don’t actually have to watch Orion to see the shower. Meteors can appear anywhere in the sky. Because Orion needs to rise high above the horizon to see the maximum numbers of meteors, best views will be obtained after midnight until dawn. Of the highest number of meteors visible (usually around 10-20 per hour), about half of these leave persistent trains (meteor trails). When you see one, you are actually seeing a tiny fragment of Halley’s Comet, which next will pass close to Earth in the year 2061.
MOON PHASES
The October Full Hunter’s Moon is also the Full Harvest Moon in 2009, and it will rise on the evening of Saturday, October 3 and set on the morning of Sunday, October 4. The October last quarter Moon occurs on Sunday morning October 11. The October new moon occurs on Sunday, October 18. The October 2009 first quarter Moon will occur on Sunday evening, October 25.
Note: Additional information can be accessed by phone at Flandrau Science Center’s Astronomy Newsline at (520) 621-4310 or as a menu option at 621-S-T-A-R.
Graphics done using Starry Night Enthusiast and Adobe Photoshop. To purchase Starry Night Enthusiast go to http://StarryNight.com