Sky at a Glance | January 7th, 2011

Friday, January 7

  • This is the coldest time of year on average (for northern latitudes). But look low in the east-northeast after 9 or 9:30 p.m. and there you'll see Regulus and the Sickle of Leo already on the rise — a distant foreshadowing of the coming of spring.

    The scene around 9 p.m.
    The waxing Moon currently passes well north of Jupiter. (These scenes are drawn for the middle of North America. European observers: move each Moon symbol a quarter of the way toward the one for the previous date. For clarity, the Moon is shown three times its actual apparent size.)

    Saturday, January 8

  • The waxing crescent Moon is closing in on Jupiter day by day, as shown in the mid-evening (9 p.m.) view here.

  • Venus is at greatest eastern elongation, 47° west of the Sun in the morning sky — the bright "Morning Star" in the southeast. Mercury too is at greatest morning elongation (23° west of the Sun) just one day later. Look for Mercury far to Venus's lower left; don't confuse it with Antares closer below Venus. See the scene under "This Week's Planet Roundup" below.

    Sunday, January 9

  • The crescent Moon shines to the right or lower right of Jupiter, as shown here. Jupiter is positioned nearly on the ecliptic, but the Moon is currently traveling 5° north of the ecliptic, which is why it misses Jupiter by such a wide margin.

  • In a telescope, Jupiter's Great Red Spot crosses the planet's central meridian around 8:34 p.m. Eastern Standard Time.

  • A little later, Jupiter's satellites Callisto and Europa are both in front of Jupiter's face (and thus hard to see, if not invisible) from 7:49 to 8:13 p.m. Pacific Standard Time (9:49 to 10:13 p.m. Central Standard Time).

    Monday, January 10

  • The waxing Moon is now above or upper right of Jupiter.

    Tuesday, January 11

  • A small telescope will show Jupiter's moon Europa gradually reappearing out of eclipse from Jupiter's shadow around 8:05 p.m. Pacific Standard Time, just east of the planet. For a complete listing of all of Jupiter's satellite events this month, good worldwide, see the January Sky & Telescope, page 40.

    Wednesday, January 12

  • First-quarter Moon (exact at 6:31 a.m. EST on this date). Look above the Moon this evening for the little constellation Aries.

    Thursday, January 13

  • Aries is now to the right of the Moon.

    Friday, January 14

  • In this coldest time of the year, the Little Dipper hangs straight down from Polaris after dinnertime as if (per Leslie Peltier) from a nail on the cold north wall of the sky.

  • Jupiter's Great Red Spot crosses the planet's central meridian around 7:44 p.m. Eastern Standard Time.

    Saturday, January 15

  • The gibbous Moon shines between Aldebaran and the Pleiades, high above Orion in early evening. Look below Orion for Sirius.



    Sky at a Glance is now an iPhone app! Put S&T SkyWeek on your iPhone, iPad, or iPod Touch and get the above listings anytime, anywhere — with interactive sky maps! Tap a button to see the scene described, customized for your location worldwide. From there you can scroll the view all around the sky, zoom in or out, change to any time or date, and turn on animation. Go to Apple's iTunes store from your device and buy S&T SkyWeek — just 99 cents!


    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 map in the center of each issue of Sky & Telescope, the essential magazine of astronomy. Or download our free Getting Started in Astronomy booklet (which only has bimonthly maps).

    Sky Atlas 2000.0 (the color Deluxe Edition is shown here) plots 81,312 stars to magnitude 8.5. That includes most of the stars that you can see in a good finderscope, and typically one or two stars that will fall within a 50× telescope's field of view wherever you point. About 2,700 deep-sky objects to hunt are plotted among the stars.
    Alan MacRobert

    Once you get a telescope, to put it to good use you must have a detailed, large-scale sky atlas (set of charts). The standards are the
    Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger Sky Atlas 2000.0 (stars to magnitude 8.5); and the even larger and deeper Uranometria 2000.0 (stars to magnitude 9.75). And read how to use your charts effectively.

    You'll also want a good deep-sky guidebook, such as Sky Atlas 2000.0 Companion by Strong and Sinnott, or the more detailed and descriptive Night Sky Observer's Guide by Kepple and Sanner, or the classic if dated Burnham's Celestial Handbook.

    Can a computerized telescope take their place? I don't think so — not for beginners, anyway, and especially not on mounts that are less than top-quality mechanically. 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."


    This Week's Planet Roundup

    As the week progresses, Venus will creep down a little toward Mercury, while the starry background including Antares slides toward the upper right. The blue 10° scale is about the width of your fist held at arm's length.

    Mercury (magnitude –0.3) is having an excellent morning apparition for skywatchers in the Northern Hemisphere. Look for it low in the east-southeast, far lower left of bright Venus, about 60 to 45 minutes before your local sunrise time. Look also for Antares much closer below below Venus.

    Venus (magnitude –4.6) blazes as the "Morning Star" in the southeast before and during dawn. In fact Venus rises some two hours before the first glimmer of dawn (for mid-northern latitudes) — a weird UFO of a thing low in the east-southeast.

    Look for Saturn and Spica very far to Venus's upper right in the south, and Arcturus even higher above Venus.

    Mars is lost behind the glare of the Sun.

    Jupiter (magnitude –2.3, at the Pisces-Aquarius border) shines high in the south as the stars come out, then lower in the southwest later in the evening. Jupiter is the brightest starlike point in the evening sky, but it sets by 10 or 11 p.m. now. In a telescope it has shrunk to only 38 arcseconds wide as Earth rounds to the far side of the Sun from it. But keep watch on Jupiter's South Equatorial Belt re-forming, as dark markings spread east and west around the globe from the storm spot that broke out in the SEB's latitude in November.

    Jupiter on Jan. 9, 2011
    Jupiter's South Equatorial Belt (above center) continues to thicken and strengthen, even as Jupiter recedes into the distance for Earthly observers. Note the SEB's ragged, gray appearance compared to the smoother, red-brown North Equatorial Belt. (South is up.)


    Christopher Go in the Philippines took this stacked-video image at 10:30 UT January 9, 2011, when the longitude on Jupiter's central meridian was 315° (System II).

    Jupiter's Great Red Spot is near System II longitude 157°. Assuming it stays there, here are all of the Great Red Spot's predicted transit times for the rest of this season.

    Saturn (magnitude +0.7, in Virgo) rises around midnight but is best seen in a telescope high in the south before dawn (far upper right of brilliant Venus). Don't confuse Saturn with Spica below or lower left of it.

    In a telescope, Saturn's new white spot has grown and spread far around the planet! See the pictures below and our article Saturn's New Bright Storm. Here are predicted transit times of the storm's original outbreak site across the center of Saturn's disk.

    Saturn's rings, meanwhile, have widened to 10° from edge-on, the widest they've appeared since 2007. And see how many of Saturn's satellites you can identify in your scope using our Saturn's Moons tracker.

    Saturn with white storm, Jan. 2, 2010
    ," he writes. South is up." credits="Donald C. Parker" width="" height="" align="right"]
    Uranus (magnitude 5.9) remains less than 1½° from Jupiter this week.

    Neptune (magnitude 7.9, at the Capricornus-Aquarius border) is sinking into the sunset.

    Pluto (magnitude 14, in Sagittarius) is hidden in the background of Mercury in the glow of dawn. Pluto is at its highest in the evening in summer (Northern Hemisphere summer).


    All descriptions that relate to your horizon — 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 Standard Time (EST) equals Universal Time (also known as UT, UTC, or GMT) minus 5 hours.


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