Sky at a Glance | January 2nd, 2009

Some daily events in the changing sky for January 2 – 10.

In early January, bright Venus points the way toward where to hunt for Mercury and Jupiter after sunset. Their brightnesses are exaggerated here.


These diagrams are drawn for 40° north latitude (New York, Denver, Madrid). If you're south of there, Mercury and Jupiter will be easier to see. If you're north of there, they'll be harder.

Alan MacRobert

Friday, January 2

  • The brief Quadrantid meteor shower peaks around dawn Saturday morning... the coldest time of the night in the coldest time of the year. And if the sky is clear, there'll be radiational cooling too. Dress for it! Meteor watching in winter is an adventure.

    The best chance of catching the shower's peak, due to its timing, will be from the Pacific time zone of North America. The Moon conveniently sets in late evening before the good meteor-watching hours begin. See the January Sky & Telescope, page 71, for more.

    Saturday, January 3

  • Right after dinnertime, it's Orion-Stack time. That is, Orion and some of his best-known companions form a big vertical stack in the southeast (if you live in the world's mid-northern latitudes). Start with Orion himself. In his middle, the three stars of Orion's Belt are stacked nearly vertically. The Belt points up toward orange Aldebaran, about two fist-widths at arm's length above. Poised higher over Aldebaran is the little Pleiades cluster. In the other direction, Orion's Belt points almost straight town to bright Sirius rising in Canis Major, about two fists below.

  • Also after dinnertime, look for the Great Square of Pegasus to the right of the Moon in the west. It's tilted onto one corner.

    Sunday, January 4

  • First-quarter Moon (exact at 6:56 a.m. EST).

  • Earth is at perihelion, its closest to the Sun for the year (just 3% closer than at aphelion in July).

    Monday, January 5

  • Are you keeping an eye on Mira when you step outside on a clear evening? Mira is the prototype of the red long-period variable stars. It shone at its peak brightness, about magnitude 3.4, in mid- and late December, easily visible to the unaided eye. It should now be starting to fade a bit. Here is Mira's location in Cetus, and here is a closer-up chart with comparison-star magnitudes (given to the nearest tenth, with the decimal point omitted).

    Tuesday, January 6

  • The Moon is very high toward the south in early evening. Spot the Pleiades to its left, by about a fist-width at arm's length.

    Jupiter is getting ever lower below Mercury. Can you still find it?
    The blue 10° scale is about the size of your fist at arm's length.
    Alan MacRobert

    Wednesday, January 7

  • This evening the Pleiades are to the right of the Moon, and Aldebaran is below it. They cap the Orion Stack; see January 3.

    Thursday, January 8

  • Although it's still only early January, a sign of the distant springtime is already up in the evening sky. Look for the Big Dipper nearly standing on its handle in the northeast. The Dipper has begun its long seasonal rise to shine nearly overhead in May and June.

    Friday, January 9

  • The frosty gibbous Moon shines in the feet of Gemini, just about halfway between Capella (high to the Moon's upper left in early evening) and Procyon (far to the Moon's lower right).

    Saturday, January 10

  • The eclipsing variable star Algol (Beta Persei) should be at minimum light, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 1:07 a.m. Sunday morning EST; 10:07 p.m. Saturday evening PST. Algol takes several additional hours to fade and to rebrighten.


    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 that's less than one star in an entire telescopic field of view, on average. By comparison, Sky Atlas 2000.0 plots 81,000 stars to magnitude 8.5, typically one or two stars per telescopic field. Both atlases include many hundreds of deep-sky targets — galaxies, star clusters, and nebulae — among the stars.
    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 note, "the sky never becomes a friendly place."

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


    This Week's Planet Roundup

    Mercury (magnitude –0.6) having a fine evening apparition low in the southwest after sunset, very far to the lower right of Venus. Jupiter remains visible below Mercury early in the week; see the twilight scenes above, and bring binoculars.

    Visually, Venus is pure white — any markings in its cloud deck are so subtle that there's always doubt about their reality. In ultraviolet light, however, it's a different story. And with stacked-video imaging, amateurs have been able to take extraordinary ultraviolet images like this. With Venus approaching dichotomy (half phase), veteran imager Don Parker of Coral Gables, Florida, captured this view in broad daylight on December 28, 2008, through an Astrodon UV Venus filter using a 10-inch Mewlon telescope at f/24.
    Donald C. Parker

    Venus (magnitude –4.5) is the dazzling "Evening Star" in the southwest during and after twilight. In a telescope Venus is now 21 arcseconds wide and even nearer to dichotomy than in the December 28th image at right (taken in ultraviolet light).

    Venus will be exactly 50% illuminated, as seen from Earth, on the evening of January 16th. But because the sunlight illumination is dimmer at the terminator, in a telescope the waning Venus usually looks exactly half-lit 5 or 10 days earlier than when it really is. How well can you determine the date of apparent dichotomy? Telescopically, Venus is best seen in bright twilight or even broad daylight (it's less glary then).

    Mars remains hidden deep in the glare of sunrise.

    Jupiter (magnitude –1.9) is sinking below the horizon far to Venus's lower right, and a little to the lower right of Mercury. Look for it early in the week, and bring binoculars.

    Saturn (magnitude +1.0, near the Leo-Virgo border) rises around 10 p.m. and is highest in the south around 4 a.m. Don't confuse Saturn with similarly-bright Regulus 22° (about two fist-widths at arm's length) to its upper right after they rise, and directly to its right after 4 a.m.

    On Christmas night Richard Bosman in the Netherlands took this image of Saturn at its minimum ring tilt for this apparition, 0.8°. South is up. Bosman writes, "The northern part is still bluish. There were no storms or spots on display at this meridian. Remarkable is the beauty of the very narrow ring now at the minimum. The ring is not bright white but dull gray."


    The Cassini Division is visible near the rings' ansae (ends). The shadow of the globe is cast on the ring's western (left) side just off the globe's edge. Even a small scope will show the very prominent black shadow that the rings are casting on the globe. Bosman used an 11-inch Celestron Schmidt-Cassegrain telescope and an ATK-2HS camera at 5:02 UT Dec. 26, 2008.


    This week Saturn's rings are 0.8° or 0.9° from edge on, essentially unchanged from last week's minimum (can you detect any difference?). The rings will gradually open to 4° by late May, then will close to exactly edge-on early next September — when, unfortunately, Saturn will be out of sight in conjunction with the Sun.

    Saturn will again be poorly placed for our next ring-plane crossing 15 years hence. So now is the thinnest you can see Saturn's rings until 2038! (I intend to be healthy and at the eyepiece then at age 87, but you never know.)

    Uranus and Neptune (magnitudes 5.9 and 7.9, respectively, in Aquarius and Capricornus) are in the southwest right after dark. Neptune is near Venus. Use our article and finder charts online or the chart in the September Sky & Telescope, page 63.

    Pluto is hidden in the glow of sunrise.

    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 Standard Time (EST) equals Universal Time (known as UT, UTC, or GMT) minus 5 hours.


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