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This Week's Sky at a Glance

by Alan M. MacRobert

"Rational and innocent entertainment of the highest kind."
— John Mills, 19th century Scottish manufacturer and founder of Mills Observatory, on amateur astronomy.

Some daily events in the changing sky for November 29 – December 6.

Looking southwest in twilight
Don't miss the best naked-eye sky spectacle of the year! (These scenes are always 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. In the Far East, move the Moon symbols halfway. For clarity, the Moon is shown three times actual size.)
Sky & Telescope diagram
Friday, November 28

  • Bright Jupiter shines 3° above even brighter Venus during twilight this evening. Watch them change configuration daily!

  • The eclipsing variable star Algol should be in one of its periodic dimmings tonight, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 12:50 a.m. Saturday morning EST; 9:50 p.m. Friday evening PST. Algol takes several additional hours to fade and to rebrighten. Use our comparison-star chart.

    Saturday, November 29

  • With Venus and Jupiter just 2.4° apart at dusk, the thin crescent Moon steps onstage about 20° to their lower right (at the time of twilight in North America), as shown here.

    Sunday, November 30

  • Venus and Jupiter are closest, 2° apart, today and tomorrow. It's purely a coincidence that the Moon shines so close to them on these dates as well!

    Monday, December 1

  • The Moon shines close to Venus and Jupiter at the time of twilight in the Americas, but it actually occults (covers) Venus as seen from western Europe! See the article and maps in the December Sky & Telescope, page 67. If you're placed just right in Europe for the best view of this event, alert your local news media to the coming naked-eye spectacle!

  • Algol should be at minimum light for a couple hours centered on 9:39 p.m. EST.

    Tuesday, December 2

  • First-magnitude Fomalhaut shines due south right after dark. Fomalhaut is one of the stars that made news last month with the announcement of the first direct images of extrasolar planets orbiting them. Another such star is 6th-magnitude HR 8977 in the western side of the Great Square of Pegasus, much higher in the south high above Fomalhaut. See our article (with finder chart).

    Wednesday, December 3

  • Spot the fingertip-sized Pleiades star cluster shining due east after dinnertime this week. Below the Pleiades glares orange Aldebaran. Much farther below Aldebaran, Orion looms up into good view by about 8 p.m. Below Orion, sparkly-bright Sirius clears the horizon after about 9 or 10.

    Thursday, December 4

  • The red long-period variable star R Aquilae should be at maximum light (6th magnitude) this week. Another red variable, Chi Cygni, in the same part of the sky should peak at 5th magnitude next week; see the comparison-star chart in the December Sky & Telescope, page 68.

  • Algol should be at minimum light for a couple hours centered on 6:38 p.m. EST.

    Facing southwest in late twilight
    Jupiter and Venus are now drawing apart.
    Sky & Telescope diagram
    Friday, December 5

  • First-quarter Moon (exact at 4:26 p.m. Eastern Standard Time).

    Saturday, December 6

  • Although it's just a little thing compared to Venus and Jupiter in the southwest, Vega is the brightest star high in the west-northwest after dark. Look higher above it for Deneb. Look farther to Vega's left for Altair. These three form the big Summer Triangle.

  • Vesta, the brightest asteroid, is a month past opposition and magnitude 7.1. It's still quite visible with binoculars near the head of Cetus. Use the finder chart in the November Sky & Telescope, page 67, or online.




    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 note, "the sky never becomes a friendly place."

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




    This Week's Planet Roundup

    As it moves farther westward in the evening sky, Jupiter has gotten small (34 arcseconds wide this week) and low, so don't be disappointed if your scope shows very little on it. Even world-class planetary imager Christopher Go recorded only this rather fuzzy view on November 16th (at 9:43 UT).

    South is up, to match the view in many telescopes. Note the white outbreak in the South Equatorial Belt near the central meridian. The CM II longitude was 277°.

    Christopher Go
    Venus and Jupiter, the two brightest planets (magnitudes –4.2 and –2.0 respectively), blaze strikingly close together in the southwest in evening twilight. They reach conjunction, 2° apart, on November 30th and December 1st — when the crescent Moon joins in too, as shown above. Watch them change their configuration daily. After conjunction, Jupiter starts moving off to Venus's right and then (by week's end) lower right.

    In a telescope Venus is still small (16 or 17 arcseconds wide) and gibbous (68% illuminated). Jupiter is 34″ wide but has a much lower surface brightness; being 7 times farther from the Sun, Jupiter is lit only about 1/49 as brightly.

    Mercury and are hidden in the glare of the Sun.

    Saturn (magnitude +1.1, near the hind foot of Leo) rises around midnight or 1 a.m. and shines very high in the south by dawn. Don't confuse Saturn with similarly-bright Regulus 20° (two fist-widths at arm's length) to its upper right.

    Saturn on Nov. 22, 2008
    Saturn's rings were tilted just 1.5° from edge-on when Christopher Go took this image on November 22, 2008. Note their very prominent shadow on Saturn's globe. South is up.
    Christopher Go
    A telescope will show that Saturn's rings have closed to just 1° from edge on. They'll reach a minimum of 0.8° at the end of December, then start opening again before finally closing to exactly edge-on next September.

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

    Pluto is hidden in the glare of the Sun.

    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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