Sky at a Glance | November 23rd, 2012

Friday, November 23

  • Altair is the brightest star in the west-southwest. (It's far lower left of brighter Vega.) Look above Altair, and perhaps a bit left, for the dim but distinctive little constellation Delphinus, the Dolphin.

    Saturday, November 24

  • Look left of the Moon this evening, by a fist-width at arm's length or a little more, for the two or three brightest stars of Aries.

    Sunday, November 25

  • Some pre-telescopic astronomy: Sometime between 6:30 and 8:30 these evenings, depending on the date and how far east or west you live in your time zone, bright Vega sinking in the northwest and equally bright Capella climbing in the northeast will be at exactly the same height. How accurately can you time this event for your location? An astrolabe would help!

    Monday, November 26

  • As dawn begins on Monday and Tuesday mornings, look southeast to spot bright Venus and fainter Saturn less than 1° apart. As dawn brightens further, look far to their lower left for Mercury.

    As the Moon becomes full, it moves in on Jupiter and Aldebaran. It's positioned here for the middle of North America. European skywatchers: move each Moon symbol a quarter of the way to the one for the previous date. In the Far East, move it halfway. For clarity, the Moon is shown three times its actual apparent size.

    Tuesday, November 27

  • Full Moon tonight and tomorrow night. This evening, look lower left of the Moon for Jupiter and orange Aldebaran. Look upper left of the Moon for the fainter Pleiades cluster (binoculars help), and far left for Capella (out of the frame here).

  • A weak penumbral eclipse of the Moon occurs before and/or during dawn Wednesday morning for western North America. The penumbra is the pale outer fringe of Earth's shadow. The Moon will be deepest in it from 6:18 to 6:48 a.m. PST on Wednesday the 28th (14:18 to 14:48 on the 28th Universal Time). Look for a weak shading on the Moon's north (upper right) side. The farther in from the West Coast you are, the brighter the dawn and the lower the Moon will be.

    The penumbral eclipse takes place high in the middle of the night for the longitudes of Australia and Japan, in late evening of the 28th local date for China and Southeast Asia, and early that evening for India with the Moon still low in the east. More details.

    Wednesday, November 28

  • The Moon shines close to Jupiter and Aldebaran this evening, with the dimmer Pleiades above them. Think photo opportunity! Use a long (or zoomed) lens, and try a variety of exposures to catch the faint stars as well as the bright Moon.

    Thursday, November 29

  • After the Moon rises this evening, spot Jupiter and fainter Aldebaran to its upper right, and Capella farther to its upper left.

  • Jupiter's Great Red Spot should cross Jupiter's central meridian around 11:00 p.m. EST (8:00 p.m. PST).

    Friday, November 30

  • The waning Moon rises less than an hour after the end of twilight. Once it's up, look right of it, by a bit more than a fist-width at arm's length, for orange-red Betelgeuse sparkling in Orion's shoulder.

    Saturday, December 1

  • With Jupiter just about at opposition, so are the asteroids Ceres and Vesta in the same vicinity! Vesta has brightened to magnitude 6.6, Ceres 7.2. Spot them in binoculars using our finder chart in the December Sky & Telescope, page 50, or online. They're near the horns of Taurus. The darkest view comes shortly before the Moon rises around 7 p.m., depending on your location.


    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 guide to 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'll need a detailed, large-scale sky atlas (set of charts). The standards are the little Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger and deeper Sky Atlas 2000.0 (stars to magnitude 8.5); and the even larger Uranometria 2000.0 (220 charts, with stars to magnitude 9.75). And read how to use sky charts with a telescope effectively.

    You'll also want a good deep-sky guidebook, such as Sue French's Deep-Sky Wonders collection (which includes its own charts), Sky Atlas 2000.0 Companion by Strong and Sinnott, the bigger Night Sky Observer's Guide by Kepple and Sanner, or the beloved if dated Burnham's Celestial Handbook.

    Can a computerized telescope replace charts? Not for beginners, I don't think, and certainly not on mounts and tripods that are less than top-quality mechanically (able to point with better than 0.2° repeatability). As Terence Dickinson and Alan Dyer say in their invaluable 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

    Dawn view
    Three planets await your capture in the dawn. (The visibility of the fainter ones in bright dawn is exaggerated here.)

    Mercury emerges into dawn view around November 24th or so, brightening from magnitude +1 to 0 this week. Look for it just above the east-southeast horizon in early dawn, far to the lower left of Venus and Saturn as shown here. Mercury is beginning its best apparition of the year for viewers at mid-northern latitudes.

    Venus, brilliant at magnitude –3.9, and Saturn, much fainter at magnitude +0.6, shine together in the southeast during dawn. Saturn begins the week 3° to Venus's lower left (on Saturday morning the 24th). It passes about 0.8° by Venus on the 26th and 27th, and by November 30th it's 4° to Venus's upper right.

    Mars (magnitude +1.2, in Sagittarius) remains low in the southwest in evening twilight. In a telescope it's just a tiny blob 4.4 arcseconds in diameter.

    Ceres and Vesta, the two brightest minor planets (asteroids), are now magnitudes 7.2 and 6.6 respectively, and located not far from Jupiter. Find them with our chart in the December Sky & Telescope, page 50, or online.

    Jupiter (magnitude –2.8, in Taurus) rises in the east-northeast in early twilight and climbs higher all evening. Orange Aldebaran is 5° to its right or lower right. Above them are the Pleiades. Jupiter is nearly at its December 2nd opposition; it appears a big 48 arcseconds wide, essentially as large as it will become this year. See "Turmoil on Jupiter" in the November Sky & Telescope, page 56.

    Jupiter at 3:33 UT Nov. 23, 2012
    The Great Red Spot's side of Jupiter is busy indeed. On Thanksgiving evening, November 22nd, Sky & Telescope imaging editor Sean Walker shot this image with his 12.5-inch Newtonian reflector and DMK21AU618 planetary video camera from New Hampshire. South is up. From upper left, note the orange ring of Oval BA, the tiny dark-red dot following it, the Great Red Spot in its white Red Spot Hollow, and the huge turbulence behind it roiling the South Equatorial Belt.


    The South Temperate Belt is barely visible along some of its length but prominent on the following side of the Great Red Spot. Four white ovals dot the South South Temperate Belt. On the north side of the planet, the North Equatorial and North Temperate belts have become cleanly separated by the North Tropical Zone's return to whiteness. Blue festoons intrude into the bright Equatorial Zone. The satellite to the left is sulfur-colored Io.

    S&T: Sean Walker

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    Uranus (magnitude 5.8, in Pisces) and Neptune (7.9, in Aquarius) are conveniently placed in the south in early evening. Finder charts for Uranus and Neptune.


    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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