Sky at a Glance | February 11th, 2011

Jupiter on Feb. 11, 2011
"Jupiter is getting more difficult now," writes imager Christopher Go in the Philippines. He caught this view of the re-formed South Equatorial Belt (above center) in twilight on February 11th just before Jupiter disappeared behind his building's roof.


The Great Red Spot is at left. "The SEB is already red in this area and it is also very turbulent," he notes. "The NEB is dark red, and note the dark and white ovals on the NEBn." South is up.


Friday, February 11

  • Jupiter's South Equatorial Belt has reappeared for small telescopes, as seen at right, after more than a year of being hidden by overlying white ammonia clouds. Jupiter shines brightly in the west-southwest at the end of twilight.

  • The first-quarter Moon shines near the Pleiades after dusk (for the time zones of the Americas). Binoculars give a fine view. Watch the Moon move with respect to the cluster along its orbit as the hours pass.

    Saturday, February 12

  • The Moon shines in Taurus this evening, inside the broad triangle formed by Aldebaran, the Pleiades, and Elnath (Beta Tauri).

  • Algol in Perseus is at its minimum brightness for a couple hours centered on 7:07 p.m. EST.

    Sunday, February 13

  • The Moon this evening shines high above Orion, near the horns of Taurus: Beta (β) and Zeta (ζ) Tauri.

    Monday, February 14

  • Early Tuesday morning, the Moon occults (covers) the 3.7-magnitude star Zeta (ζ) Geminorum for much of North America. The Moon's dark edge will cover the yellow star at a different time for every location. Examples: Toronto, 3:54 a.m. EST; Atlanta, 4:11 a.m. EST; Chicago, 2:50 a.m. CST; Denver, 2:04 a.m. MST. Map and full timetables of the star's disappearance and reappearance.

    Tuesday, February 15

  • The Moon this evening forms part of a gently arcing line with Castor and Pollux to its upper left and Procyon to its lower right.

    Wednesday, February 16

  • The Big Dipper stands on its handle high in the northeast these evenings. Its top two stars, the Pointers, point left to the (rather dim) North Star — about three fists at arm's length away.

    Thursday, February 17

  • Full Moon tonight (exact at 3:36 a.m. Friday morning EST).

  • Look left or lower left of the Moon after dark for Regulus. Farther left of them is Gamma Leonis, not much fainter than Regulus. Look farther to the Moon's lower right for orange Alphard.

    Friday, February 18

  • Look for Regulus about a fist-width above the Moon this evening. Regulus marks the bottom-right end of the Sickle pattern in Leo (the bottom of the Sickle's handle).

    Saturday, February 19

  • This is the time of year when Orion stands at his highest due south in early evening. Upper right of him is Taurus with orange Aldebaran and, farther on, the Pleiades cluster. Lower left of Orion is Canis Major with bright Sirius.



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    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
    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 sky 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

    Saturn on Feb. 6, 2011
    Saturn's new white spot now "looks like a comet," writes Christopher Go. This image exaggerates its contrast, but even visually "it is very distinct" in Go's 11-inch scope. He also noted that the North Equatorial Belt "is red and distinct now." South here is up.


    Click for animation of several images spanning 33 minutes of Saturn's rotation. This one was shot at 18:50 UT Feb. 6, 2011, when the System III central-meridian longitude was 50°.


    And see an even more awesome Cassini image.

    Mercury, Mars, and Neptune are hidden behind the glare of the Sun.

    Venus (magnitude –4.2, in Sagittarius) shines as the "Morning Star" in the southeast before and during dawn.

    Jupiter (magnitude –2.1, at the Pisces-Cetus border) shines brightly in the west-southwest at dusk and sets in the west around 9 p.m. Get your telescope on it in late twilight while it's still high. Jupiter has shrunk to only 35 arcseconds wide, but keep watch on its South Equatorial Belt re-forming.

    Saturn (magnitude +0.6, in Virgo) rises around 10 p.m., but it's best seen in a telescope at its highest in the south in the early-morning hours (it transits around 3 a.m.). Don't confuse Saturn with Spica 8° or 9° below it during evening, and lower left of it before dawn.

    Saturn on Feb. 11, 2011
    is on the other side of the planet, this area is still bright. The head has basically moved more than half around the planet now. The South Equatorial Belt can be seen just south of the ring." South is up." credits="Christopher Go" width="" height="" align="right"]
    In a telescope, Saturn's new white spot has spread into a double streak far around the planet, as seen here. Saturn's rings are 10° from edge on, their maximum for this year. See how many of Saturn's satellites you can identify in your scope using our Saturn's Moons tracker.

    Uranus (magnitude 5.9) is about 6° west (lower right) of Jupiter.


    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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