Sky at a Glance | February 27th, 2009

Some daily events in the changing sky for February 27 – March 7.

Comet Lulin is starting to fade is it moves away from both Earth and Sun. And moonlight begins returning around February 28th. Use binoculars or, preferably, a telescope. See our article and, after March 1st, this detailed chart.

On February 25th the comet went through opposition, nearly 180° from the Sun in our sky. That meant that its dim gas tail (which always points away from the Sun) appeared to switch sides and should now be aligned more or less with the brighter dust tail, formerly called the antitail.


The final Moon-Venus conjunction of this season's cycle is an eye-catcher at dusk on Friday the 27th, at least if you're in the longitudes of the Americas. European observers: move each Moon symbol a quarter of the way toward the one for the previous date. In the Far East, move the Moons halfway. The blue 10° scale is about the size of your fist held at arm's length. For clarity, the Moon is shown three times actual size.

Friday, February 27

  • Bright Venus and the crescent Moon pair up gorgeously in the western sky during and after twilight, as shown at right. Think photo opportunity! In traditional mythologies both are symbols of fertility and growth, so you can look upon their cozy pairing as a harbinger of the coming arrival of spring.

    Even in broad daylight this afternoon, the Moon provides an easy landmark for spotting Venus through a bright blue sky. They're only 2° apart in late afternoon as seen from North America, with Venus to the Moon's upper right. (See the hour-by-hour illustration in the February Sky & Telescope, page 47.) If you haven't seen Venus in daytime before, you may be surprised at how easy it is.

  • Comet Lulin is about 1° southwest of Regulus this evening (evening in the time zones of the Americas). See our article.

  • Uranus is at aphelion today, its farthest from the Sun in its 84-year orbit. So for the rest of your life, Uranus will be just a trace closer each year.

    Saturday, February 28

  • Now the waxing crescent Moon is high above Venus, leaving it behind as the Moon moves along its monthly orbit around Earth.

  • The bright eclipsing variable star Algol should be in one of its periodic dimmings, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 7:05 p.m. EST. Algol takes several additional hours to fade and to rebrighten. Use our comparison-star chart.

    Three planets before sunrise
    You'll need binoculars for this one; the visibility of objects through bright twilight is exaggerated in these scenes for clarity. The scenes are drawn for latitude 40° north, longitude 90° west, near the middle of North America. For this event, the farther south you are the higher the planets will appear. Good luck!
  • Before sunrise Sunday and Monday mornings, Mercury is within 3/4° of faint Mars very low in the east-southeast, as shown at right. Using binoculars, look for them 7° lower left of brighter Jupiter.

    Sunday, March 1

  • This is the time of year when, shortly after dark, the Big Dipper rising up the northeast appears the same height as Cassiopeia descending in the northwest. Both of them are standing on end.

    Monday, March 2

  • The Pleiades sparkle above the Moon this evening.

    Tuesday, March 3

  • First-quarter Moon tonight (exact at 2:46 a.m. Wednesday morning EST).

  • Ceres, magnitude 7.0, is 1/3° north of the fine telescopic double star 54 Leonis (whose components are magnitudes 4.6 and 6.3, separation 6.6 arcseconds).

    Wednesday, March 4

  • The Moon this evening is almost exactly halfway between Betelgeuse (to the Moon's lower left) and Capella. It's two fist-widths at arm's length from each.

    Thursday, March 5

  • For North Americans, a dawn challenge: On Friday morning about 40 minutes before sunrise, get a telescope on Jupiter just above the east-southeast horizon. Can you see the 4th-magnitude star Theta Capricorni 0.1° to Jupiter's southeast? Callisto, Jupiter's outermost large satellite, lies a similar distance to the planet's northeast. But Theta Cap noticeably outshines all of Jupiter's moons.

    Friday, March 6

  • The Moon is high overhead this evening near Pollux and Castor in Gemini.

    Saturday, March 7

  • Daylight saving time, observed in most of North America, begins at 2 a.m. Sunday morning. Clocks "spring ahead" one hour. Be sure to make this change in our online almanac if you use it (check the Daylight Saving Time box). Daylight time for North America runs from the second Sunday in March to the first Sunday in November; the rules changed in 2007. Daylight time is not used in Hawaii, Saskatchewan, Puerto Rico, or in most of Arizona.


    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 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 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 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

    Jupiter, Mercury, and Mars (magnitudes –2.0, –0.2, and +1.2, respectively) are very low in the glow of sunrise, where they're changing configuration daily. See the March 1 sky scene above. Start by spotting Jupiter above the east-southeast horizon 30 or 40 minutes before sunrise. Fainter Mercury, and much fainter Mars, are down to Jupiter's lower left. Use binoculars.

    You can find your local sunrise time by making sure you've put your location into our online almanac. Make sure the Daylight Saving Time box is unchecked if you're still on standard time.

    Venus (magnitude –4.8, in central Pisces) is the dazzling "Evening Star" in the west during and after twilight. It's getting lower now and sets around 8:30 p.m. In the next three weeks it will plunge down away into the sunset. In a telescope, Venus is a rapidly waning crescent (waning from 20% to 13% sunlit this week). It enlarges this week from 44 to 50 arcseconds from cusp to cusp. Telescopically, Venus is best seen in bright twilight or even broad daylight; it's less glary against a bright sky, and it's higher.

    Ceres resolved with an 11-inch scope!
    Ceres was 11 days from opposition, and 0.83 arcseconds wide, when John Sussenbach of Houten, Netherlands, resolved its disk by video imaging Feb. 14, 2009. At right is a star's diffraction pattern imaged for comparison. He used a Celestron 11-inch Schmidt-Cassegrain scope with a 3× Barlow, a DMK2AF4.AS video camera, and RGB filters. In each color he took 980 frames and used Registax 4.0 to select and stack the best 500 from each. Click image for more.
    Ceres (magnitude 6.9 or 7.0, above the back of Leo) is having its closest apparition of our lifetime. This "dwarf planet," the largest of the main-belt asteroids, was at opposition on February 25th. See the article and finder chart in the March Sky & Telescope, page 60, or online.

    Ceres, with a diameter of 950 kilometers (590 miles), is estimated to contain a third of the mass of the asteroid belt — even though the main belt is thought to contain a million objects larger than 1 kilometer across.

    Saturn (magnitude +0.5, near the hind foot of Leo) will come to opposition on March 8th. It rises in twilight this week, shines well up in the east by 9 p.m., and is highest in the south around midnight. Don't confuse Saturn with similarly-bright Regulus 20° (two fist-widths at arm's length) to its upper right in early and mid-evening, and more directly to its right late at night.

    Titan was leaving Saturn's face when Christopher Go in the Philippines took these images 10 and 12 minutes apart starting at 18:00 UT February 8th. As you can see, Titan's murky orange atmosphere is darker than Saturn's bright cloudtops. (The dark ring around Titan in the first frame is an image-processing artifact.) North is up. Click image to see an animation.


    P.S.: Here are the times and dates (in UT) of all of Titan's transits, and transits of its shadow, across Saturn in 2009.

    Saturn's rings are 2° from edge on. The rings will open to 4° by late May, then will close to exactly edge-on next September 4th — when, unfortunately, Saturn will be out of sight practically in conjunction with the Sun.

    Uranus is hidden behind the glow of the Sun.

    Neptune, deep in the glow of sunrise, is hidden in the background of Mercury and Mars.

    Pluto (in northwestern Sagittarius) is in the southeast before dawn.

    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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