Sky at a Glance | October 24th, 2008

Some daily events in the changing sky for October 24 – November 1.

Two planets in twilight
Jupiter and Venus are well along in their great march toward each other. They're on their way to a fine conjunction on November 30th and December 1st. After sunset on Halloween, look for the thin Moon below Venus with much fainter Antares nearby (binoculars help).

Friday, October 24

  • During dawn Saturday, look east for Saturn to the upper left of the Moon.

    Saturday, October 25

  • Venus is passing 3½° north of Antares at dusk this evening and tomorrow evening.

  • During dawn Sunday morning, Saturn, the Moon, and Mercury form a tall tableau in the eastern sky.

    Sunday, October 26

  • Jupiter shines brightly in the southwest just after dark this week. Look very high above it for bright Altair in Aquila, the Eagle.

    Always helping to identify Altair is its little sidekick star Tarazed located a finger's width away — currently to Altair's upper right. The two may look close together, but in astronomy looks deceive. Altair is just 17 light-years away, while Tarazed is an orange giant 330 light-years distant. And though it looks dimmer (magnitude 2.7), it's actually putting out about 75 times as much light.

    Monday, October 27

  • The Ghost of Summer Suns. Halloween is approaching, and this means that Arcturus, the star sparkling low in the west-northwest in late twilight, is taking on its role as "the Ghost of Summer Suns." What does this mean? For a few days every year around October 29th, Arcturus occupies a special place in your local sky. It closely marks the spot above your horizon where the Sun stood at the same time (by the clock) during June and July — in broad daylight, of course. So at this season every year, you can think of Arcturus as the Halloween ghost of the departed summer Sun.

    Tuesday, October 28

  • New Moon (exact at 7:14 p.m. EDT).

    Wednesday, October 29

  • Vesta, the brightest asteroid, is at opposition, shining at magnitude 6.5. It's well up by late evening, easily visible with binoculars in the head of Cetus. Use the finder chart in the November Sky & Telescope, page 67.

    Thursday, October 30

  • How well do you know Capricornus and its small-telescope highlights? See Ken Hewitt-White's "Suburban Star-Hop" column in the October Sky & Telescope, page 51, to discover what you may be missing.

    Friday, October 31

  • Low in the southwest in twilight, look for the thin crescent Moon about 5° beneath Venus. Slightly to the right of the Moon (for twilight in North America) is much fainter Antares, as shown at the top of this page.

  • Halloween astronomy. If the sky is clear, why not set up your telescope in the driveway to share some astronomy with visiting trick-or-treaters and their parents? Jupiter and its four satellites are still up in early evening. Other crowd pleasers that survive a fair amount of light pollution are the open cluster M11 in the tail of Aquila and the colorful double star Albireo, Beta Cygni.

    Saturday, November 1

  • Low in the southwest at in twilight, the thin crescent Moon appears 7° or 8° left of Venus (for North America).

  • Daylight saving time, observed in most of North America, ends at 2:00 a.m. Sunday morning. Clocks "fall back" one hour. Be sure to make this change in our online almanac if you use it (uncheck the Daylight Saving Time box). Daylight time for North America runs from the second Sunday in March to the first Sunday in November; the rules changed in 2007. Daylight time is not used in Hawaii, Saskatchewan, Puerto Rico, or in most of Arizona.

  • Before dawn Sunday morning, a telescope will show the 4.0-magnitude star Sigma Leonis just 0.1° from Saturn.


    Want to become a better amateur astronomer? Learn your way around the constellations. They're the key to locating everything fainter and deeper to hunt with binoculars or a telescope. For an easy-to-use constellation guide covering the whole evening sky, use the big monthly foldout map in each issue of Sky & Telescope, the essential magazine of astronomy. Or download our free Getting Started in Astronomy booklet (which only has bimonthly maps).

    Pocket Sky Atlas
    The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6 — which may sound like a lot, but it's still less than one per square degree on the sky. Also plotted are many hundreds of good telescopic galaxies, star clusters, and nebulae.
    Sky & Telescope
    Once you get a telescope, to put it to good use you'll need a detailed, large-scale sky atlas (set of maps; the standards are
    Sky Atlas 2000.0 or the smaller Pocket Sky Atlas) and good deep-sky guidebooks (such as Sky Atlas 2000.0 Companion by Strong and Sinnott, the even more detailed Night Sky Observer's Guide by Kepple and Sanner, or the classic Burnham's Celestial Handbook). Read how to use them effectively.

    Can a computerized telescope take their place? As Terence Dickinson and Alan Dyer say in their Backyard Astronomer's Guide, "A full appreciation of the universe cannot come without developing the skills to find things in the sky and understanding how the sky works. This knowledge comes only by spending time under the stars with star maps in hand and a curious mind." Without these, they wisely say, "the sky never becomes a friendly place."

    More beginners' tips: "How to Start Right in Astronomy".



    This Week's Planet Roundup

    Mercury (magnitude –0.8) is having its best morning apparition of 2008. Look for it low in the east, far below Saturn and perhaps a bit left, about 60 to 45 minutes before sunrise. See the illustration at the top of this page.

    You can always find your local sunrise time, and much else, once you put your location into our online almanac. If you're on daylight saving time, make sure the Daylight Saving Time box is checked.

    Near Venus, Can you still see Antares through the sunset afterglow?
    Alan MacRobert
    Venus (bright at magnitude –3.8) is getting higher and more prominent after sunset. Look for it above the southwest horizon in twilight. Binoculars will help you spot Antares lower left of Venus early in the week, and directly below it later in the week.

    Mars is lost in the sunset.

    Vesta, the brightest asteroid, is easily spottable with binoculars at magnitude 6.5 in the head of Cetus. It gets high late in the evening. Use the finder chart in the November Sky & Telescope, page 67.

    Jupiter (bright at magnitude –2.2, in Sagittarius) shines in the south-southwest in twilight, but lower in the southwest later — so get your scope on it early!

    In the coming month watch Jupiter close in on Venus, which is currently far to its lower right, by 1° per day. They're 38° apart on October 24th and 31° on the 31st. These two brightest planets are heading toward a spectacular conjunction, 2° apart, on November 30th and December 1st.

    Saturn shines in the east before and during dawn. Don't confuse it with fainter Regulus about 18° (roughly two fist-widths at arm's length) to its upper right. A telescope will show that Saturn's rings have turned nearly edge on; they're currently tilted 2° to our line of sight and closing. They'll reach a minimum of 0.8° at the end of the year, then start opening again.

    Uranus and Neptune (magnitudes 5.8 and 7.9, respectively, in Aquarius and Capricornus) are in the southeast and south during evening. Use our article and finder charts or the chart in the September Sky & Telescope, page 63.

    Pluto (magnitude 14) is getting low in the southwest after dark.

    All descriptions that relate to your horizon or zenith — including the words up, down, right, and left — are written for the world's mid-northern latitudes. Descriptions that also depend on longitude (mainly Moon positions) are for North America. Eastern Daylight Time (EDT) equals Universal Time (known as UT, UTC, or GMT) minus 4 hours.


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