Sky at a Glance | October 30th, 2009

Some daily events in the changing sky for October 30 – November 7

Two planets accompany stars of Virgo in the east-southeast at dawn. This is their configuration on the morning after Halloween night. The visibility of faint objects in bright twilight is exaggerated here; you may need binoculars for all but Venus.

Friday, October 30

  • Watch in a telescope tonight as Jupiter's moon Ganymede partially occults the slightly fainter moon Europa, from 11:55 p.m. to 12:03 a.m. EDT (8:55 to 9:03 p.m. PDT). They'll be west of the planet; watch them appear to merge and then separate as the minutes tick by. For a complete list of such mutual events among Jupiter's satellites visible from North America through the end of the year, see the October Sky & Telescope, page 56.

    Saturday, October 31

  • Mars shines in the east during the early morning hours of Sunday. Binoculars will show that it's smack in the center of the Beehive star cluster, M44 — a bright candle in a ghostly Halloween pumpkin.

  • Jupiter's moon Io occults Europa partially from 11:38 to 11:43 p.m. EDT (8:38 to 8:43 p.m. PDT).

    Sunday, November 1

  • Daylight-saving time ends at 2:00 a.m. for most of the U.S. and Canada; clocks "fall back" an hour.

  • Jupiter is 1/3° north of Iota Capricorni (magnitude 4.3.) this evening through Tuesday evening.

  • Jupiter's Great Red Spot should cross Jupiter's central meridian (the imaginary line down the center of the planet's disk from pole to pole) around 8:27 p.m. Eastern Daylight Time. The "red" spot appears very pale orange-tan. It should be visible for about an hour before and after in a good 4-inch telescope if the atmospheric seeing is sharp and steady. A light blue or green filter helps. The Red Spot transits about every 9 hours 56 minutes; for all of the Red Spot's central-meridian crossing times, good worldwide, use our Red Spot calculator or print out our list for the rest of 2009.

    Monday, November 2

  • Full moon (exact at 2:14 p.m. EST)

    The Moon skims the Pleiades Tuesday night as seen from North America. These scenes are always plotted exactly for a viewer near the center of North America (at latitude 40° north, longitude 90° west). For clarity, the Moon is always drawn three times its actual apparent size.
    Tuesday, November 3

  • The Moon, barely past full, crosses the southeastern edge of the Pleiades tonight for parts of the southern U.S. and points south, from roughly 10 p.m. to 1 a.m. EST. Maps and timetables.

  • Jupiter's Red Spot transits around 10:06 p.m. EST.

    Wednesday, November 4

  • The bright Moon this evening (evening for North America) balances between the two brightest stars of Taurus: Aldebaran and Beta Tauri, as shown at right.

  • Jupiter's moon Io casts its tiny black shadow onto Jupiter's face from 7:17 to 9:26 p.m. Eastern Standard Time. (For a list of all such events among Jupiter's moons this month, good worldwide, see the November Sky & Telescope, page 47.)

    Thursday, November 5

  • Bright Capella, shining in the northeast, and equally bright Vega, in the west-northwest, will be balanced at exactly the same height above your horizon sometime around 8 or 9 p.m., depending on where you live in your time zone. How accurately can you time this event for your point on Earth?

  • Telescope users in the American West can watch Jupiter's moon Ganymede partially occult Io from 9:06 to 9:13 p.m. Pacific Standard Time.

    As the Moon wanes further, it rises later. By Saturday November 8th it's down next to Mars.
    Friday, November 6

  • Orion preview. Look low in the east around 9 or 10 p.m. (depending on where you live in your time zone), and you'll see the bright winter constellation Orion already on the rise. Above Orion is orange Aldebaran. Above Aldebaran is the fingertip-size Pleiades star cluster. The waning Moon is shining to Orion's left in the middle of Gemini, as shown at right.

  • Jupiter's Red Spot transits around 7:36 p.m. EST.

    Saturday, November 7

  • Jupiter's moon Europa reappears from eclipse out of Jupiter's shadow around 9:17 p.m. Eastern Standard Time. A small telescope will show it swelling into view just a little east of the planet.


    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).

    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 81,312 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 — to hunt 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 charts; 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 more detailed and descriptive 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? 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 and a curious mind." Without these, "the sky never becomes a friendly place."

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


    This Week's Planet Roundup

    Jupiter's Great Red Spot remains clearly separated from the South Equatorial Belt (SEB) by a wide, white Red Spot Hollow. Note the small, very dark red barges following behind. The SEB seems to be calming and fading; the NEB is darker and much busier. South is up.

    Christopher Go took these images on October 26th at 11:12 and 12:07 UT. Stacked-video images like these show much more detail than you're ever likely to see visually on Jupiter.

    Christopher Go
    Mercury is in superior conjunction, behind the glare of the Sun.

    Venus (magnitude –3.9) is sinking lower in the dawn every week. Look for it low in the east 60 to 30 minutes before your local sunrise time. Use binoculars to look for twinkly little Spica to Venus's lower right early in the week, directly right of Venus around November 4th (by 4°), and to Venus's upper right thereafter. Look too for Saturn much higher to their upper right.

    Mars (magnitude +0.4, in central Cancer) rises around 11 p.m. standard time below Castor and Pollux in the east. It's very high in the southeast before dawn. Use binoculars to watch Mars crossing the Beehive star cluster from the mornings of October 31st to November 2nd.

    In a telescope Mars is only about 8 arcseconds wide: a tiny, fuzzy gibbous blob. Mars is on its way to an unremarkable opposition late next January, when it will be 14.1 arcseconds wide.

    Jupiter (magnitude –2.4, in Capricornus) shines brightly in the south at dusk and lower in the southwest later in the evening. It sets around midnight.

    Saturn (magnitude +1.1, in the head of Virgo) is getting higher the east-southeast before and during dawn. More than 20° to its lower left is bright Venus.

    Uranus (magnitude 5.8, below the Circlet of Pisces) is well up in the south during evening.

    Neptune (magnitude 7.9, in Capricornus) is 6° east of Jupiter.

    See our finder charts for Uranus and Neptune. For a guide to spotting the challenging satellites of Uranus and Neptune at any date and time (you'll need a big scope), see the October Sky & Telescope, page 59.

    Pluto (14th magnitude, in Sagittarius) is disappearing into the sunset.

    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 (also known as UT, UTC, or GMT) minus 4 hours. Eastern Standard Time (EST) is UT minus 5 hours.

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