Sky at a Glance | March 27th, 2009

Some daily events in the changing sky for March 27 – April 4.

Watch the crescent Moon passing the Pleiades and Hyades at nightfall. (These scenes are 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. The blue 10° scale is about the size of your fist held at arm's length.)

Friday, March 27

  • Venus is at inferior conjunction, passing 8° north of the Sun. See our article.

    Saturday, March 28

  • As twilight gives way to night, look to the right of the crescent Moon in the west for the stars of little Aries (just outside the frame here). Higher to the Moon's upper left are the Pleiades.

    Sunday, March 29

  • In late dusk, the Pleiades are about 7° above the crescent Moon (seen at the time of dusk for North America), as shown at right.

    Monday, March 30

  • This evening the Pleiades are about 7° below the Moon.

    Tuesday, March 31

  • A small telescope will always reveal Titan, Saturn's largest satellite. Tonight and tomorrow Titan is three or four ring-lengths to Saturn's west.

    Wednesday, April 1

  • This evening, the Moon shines just about midway between Capella (to its right) and Procyon (to its left).

    Thursday, April 2

  • First-quarter Moon (exact at 10:34 a.m. EDT).

    Friday, April 3

  • Arcturus, the "Spring Star," sparkles brightly in the east these evenings. After about 9 or 10 p.m. look for Vega, the "Summer Star," rising low in the northeast.

    Saturday, April 4

  • The Moon this evening forms a straight, diagonal line with Regulus and Saturn to its lower left.


    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

    Mercury is hidden in the glare of the Sun.

    Venus 8.4° from the Sun
    At midday on March 25th, just two days before Venus's inferior conjunction, several Sky & Telescope staffers set up small telescopes in our back parking lot in the shadow of a building. We spotted the crescent Venus plain as could be, 8.4° north of the Sun. It looked thicker in the poor atmospheric seeing than its actual phase: just 1% illuminated. Dennis di Cicco held a camera up to the eyepiece and clicked.
    Dennis di Cicco
    Venus (magnitude –4.0) is at inferior conjunction on March 27th. But even though it's close to the Sun, this is an exciting time for Venus watchers! In a telescope it's easily seen as a hairline crescent — because at this conjunction, Venus passes a full 8° to the Sun's north.

    Telescopically, Venus is best seen in full midday daylight. Just don't let your telescope accidentally point at the Sun and blind you! Safest is to observe in the shadow of a building that will continue to block the Sun from view. For more on Venus's especially favorable conjunction phenomena this year, see our article "Venus at Its 8-Year Best".

    And already Venus is becoming visible very low in the sky of dawn. Look for it barely above the eastern horizon 10 or 15 minutes before sunrise. Don't confuse it with bright Jupiter very far to the upper right. Find your local sunrise time from our online almanac (if you're on daylight saving time like most of North America, make sure the Daylight Saving Time box is checked).

    Mars (magnitude +1.2) is very low in the sunrise glow. Using binoculars, you can try looking for it just above the east-southeast horizon, far to the lower left of much brighter Jupiter, about 30 minutes before sunrise. Good luck.

    Ceres, the largest asteroid, is magnitude 7.4 above the back of Leo. Find it with binoculars using the article and chart in the March Sky & Telescope, page 60, or online.

    Jupiter (magnitude –2.0, in Capricornus this year) shines low in the southeast during early dawn.

    On March 25th, Christopher Go in the Philippines imaged Saturn and three of its moons during excellent seeing. Dione and Tethys are on the left, and fast-moving little Enceladus is just above the rings' tip on the right. North is up, and celestial east is left.


    Go writes, "The band details are again excellent in this image. The South Equatorial Belt is well resolved. The North Equatorial Belt is still rather dull. There is a lot of banding in the South Polar Region."

    Christopher Go
    Saturn (magnitude +0.6, near the hind foot of Leo) shines in the east-southeast at dusk. It's highest in the south around 11 p.m. Look for Regulus shining 17° (nearly two fist-widths at arm's length) to Saturn's upper right in early evening, and more directly to its right later at night.

    In a telescope, Saturn's rings are 3½° from edge on. The rings will open to a maximum of 4° in 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.

    P.S.: Remember the quadruple transit of Saturnian moons across the planet's face that made news on February 24th? Hubble was looking, and the Hubble Heritage Project has released the images. Wow.

    Uranus (6th magnitude) is hidden behind the glare of the Sun.

    Neptune (8th magnitude) is deep in the glow of dawn, far in the background of Jupiter.

    Pluto (14th magnitude, 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 Daylight Time (EDT) equals Universal Time (known as UT, UTC, or GMT) minus 4 hours.


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