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October 2007

Skywatcher’s Guide for October 2007

PLANETS

This chart shows Jupiter and the Moon looking towards the southwest 45 minutes after sunset at 6:37 p.m. (MST) on Oct. 15-16 (in the evening twilight as seen from southern Arizona). This sky chart is most useful for the southern half of the USA and northern Mexico.
This chart shows Jupiter and the Moon looking towards the southwest 45 minutes after sunset at 6:37 p.m. (MST) on Oct. 15-16 (in the evening twilight as seen from southern Arizona). This sky chart is most useful for the southern half of the USA and northern Mexico.
Mars, the Moon and the eastern sky on October 1 and 29, 2007 in the evening twilight at 11:45 p.m. (MST) as seen from southern Arizona. This sky chart is most useful for the most of the USA, southern Canada and northern Mexico.
Mars, the Moon and the eastern sky on October 1 and 29, 2007 in the evening twilight at 11:45 p.m. (MST) as seen from southern Arizona. This sky chart is most useful for the most of the USA, southern Canada and northern Mexico.
Venus, Saturn, the Moon and the eastern sky are shown from October 6-7, 2007 as seen from southern Arizona at 5:15 a.m. (MST). This sky chart is useful throughout much of the USA, southern Canada and northern Mexico.
Venus, Saturn, the Moon and the eastern sky are shown from October 6-7, 2007 as seen from southern Arizona at 5:15 a.m. (MST). This sky chart is useful throughout much of the USA, southern Canada and northern Mexico.

Bright Jupiter is still visible in the October sky, but continues to lose altitude in our evening sky. Jupiter appears as a very bright, almost brilliant white star-like object, above the southwestern horizon in the early October evening twilight. By late October Jupiter moves lower into the southwestern sky and by late October Jupiter sets early above the southwestern horizon not long after the end of evening twilight for Arizona (setting earlier the farther north you live). Sinking in altitude this month, Jupiter sets above the southwestern horizon in southern Arizona by 9:30 p.m. in early October, by 9:00 p.m. mid-month, and by 8 p.m. in late October. To find Jupiter simply look for a very bright white star-like object above the south-southwestern horizon at 7 p.m. The largest planet in our solar system, Jupiter is the brightest star-like object most often seen in the night sky, although Venus is substantially brighter, and Mars can be brighter every 15 years or so. The giant gas world, although dimmed somewhat from June, remains very bright in the evening skies of Earth all month long. When looking at Jupiter in a telescope to view its cloud belts and festoons, the sharpest views should be in bright evening twilight, when it’s highest 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. Finally, the waxing crescent Moon can be seen well below Jupiter on the evening of October 15.

Mars continues to brighten and is now zero magnitude in by early October and reaches -0.6 magnitude by October 31. While it brightens Mars also enlarges in apparent size to 12 arc seconds in size, so it’s worth looking at in high quality telescopes at high power. One hour before sunrise Mars is now overhead in Gemini, the Twins and continues to drift eastward in our sky. Mars is rising now above the east-northeastern horizon at around 10:45 p.m. in early October but rises earlier each night, so that by month’s end it rises at 9:30 p.m. The Moon can be found relatively close to Mars in our sky on October 1-2, and 29/30.

Currently a Mars hoax e-mail might still be found making its way around the Internet, stating that Mars will be closest to the Earth in 60,000 years. Please go to our news story for more information.

The brilliant planet Venus remains our ‘morning star’ this month in the east and gains altitude to reach its highest possible in the pre-dawn twilight. It rises over 3.5 hours before the Sun does in early October and is highest at the end of the month, at over 40 degrees in altitude at sunrise. As Venus is now receding from Earth it slowly shrinks in apparent size in a telescope and its crescent now thickens. To the unaided eye Venus appears as an intensely bright white star that does not twinkle and is found high up in all month long above the eastern horizon, 45 minutes before sunrise. The Moon has a spectacular gathering with Venus, Saturn and the star Regulus from October 6-8: The thin waning crescent Moon is west (above) Venus on October 6 but is found closest to Saturn (and Venus) and on Sunday morning, October 7.

Saturn emerged from the glare of the Sun during September in the morning twilight above the eastern horizon and in early October has a spectacular grouping with Venus and the bright star Regulus (see above). Saturn appears as a closer to first magnitude star-like object (at magnitude 0.8), and is dimmer this year because its rings are more edge-on. In Leo the Lion and near its bright star Regulus, Saturn rises earlier and creeps higher above the eastern horizon. Saturn is found grouped near Venus from Oct. 1-21 (the two are closest from Oct. 8-18), high above the eastern horizon in the morning twilight, starting 2 hours before sunrise.

Mercury is currently lost in the glare of the Sun and not easily visible to the naked eye in the northern hemisphere.

Visitors to Flandrau’s 16-inch telescope should note that only Jupiter is visible when the telescope opens at 7 p.m. Jupiter is too low in our sky for viewing by mid-month, so visitors should come see it by 7 p.m. no later than October 12. Otherwise, no planets are currently visible in the telescope during normal operating hours. Flandrau’s main exhibit hall and planetarium are closed on Wednesdays but the telescope remains open, weather permitting Wednesday through Saturday nights (excluding select holidays). The telescope normally closes at 10 p.m.

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 right now, note that it may appear to twinkle somewhat; however, this twinkling is of a slower nature than the bright stars.

OCTOBER 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 is useful throughout much of the USA.
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 is useful throughout much of the USA.
This sky chart shows much of the early night sky in October that can be seen overhead before 9 p.m. The sky chart is valid throughout October, anywhere in the United States and Mexico. The center bottom of the sky chart is approximately above the south-southwestern horizon.
This sky chart shows much of the early night sky in October that can be seen overhead before 9 p.m. The sky chart is valid throughout October, anywhere in the United States and Mexico. The center bottom of the sky chart is approximately above the south-southwestern horizon.

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 shown here is at 1 a.m. for October 20-22. This chart is useful anywhere in the United States. The Orionid meteor shower may be best seen in the pre-dawn hours before sunrise.
The sky shown here is at 1 a.m. for October 20-22. This chart is useful anywhere in the United States. The Orionid meteor shower may be best seen in the pre-dawn hours before sunrise.

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. The best night to view the shower should be Saturday night into Sunday morning October 20-21. The Moon, won’t hinder viewing much this year (the Moon sets at around 1:20 a.m. on Oct. 21 and around 2:30 a.m. on Oct. 22). 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 last quarter Moon will occur on Wednesday morning, October 3, when it can be found not far, and north of Mars in our sky after midnight. The October new moon occurs on October 10. The first quarter Moon will be on the evening of Thursday October 18. The October full moon is called the full ‘Hunters’ Moon and occurs this year in North America on Thursday night October 25th into the morning of Friday October 26th. This is also the closest actual full moon to Earth, at only 221 thousand miles distant. This perigee full moon will result in very high tides and very low tides in ocean areas.

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

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