Sky at a Glance | March 14th, 2008

Some daily events in the changing sky for March 14 – 22.

The waxing Moon, in its eastward journey across the sky, passes by Mars on the night of Friday the 14th. (The scene is 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.)
Sky & Telescope diagram

Friday, March 14

  • First-quarter Moon (exact at 6:46 a.m. EDT).

  • Around midnight tonight Eastern Daylight Time, the Moon passes close by Mars, as shown at right.

    Saturday, March 15

  • The Moon shines in the middle of Gemini high overhead after dark.

  • Algol in Perseus is getting low in the northwest these evenings, so see if you can catch it in one of its eclipses before it disappears for the season. It should be magnitude 3.4 instead of its usual 2.1 for a couple hours centered on 9:36 p.m. Pacific Daylight Time. Algol takes several additional hours to fade and to rebrighten. Best seen from western North America. (For all times of Algol's minima this month, good worldwide, see the March Sky & Telescope, page 71.) See chart.

    Sunday, March 16

  • As winter turns toward spring, Orion's Belt turns horizontal in the southwestern sky after dark.

    Monday, March 17

  • The red long-period variable stars V Canum Venaticorum, S Hydrae, and R Corvi should be at their maximum brightnesses (7th or 8th magnitude) this week.

  • Writes David Likuski: "The asteroids 7 Iris (magnitude 9.2) and 88 Thisbe (mag. 10.9) are only 10 arcminutes apart as seen late tonight and early Tuesday morning. Although slowly separating, they will remain within ½° of each other through March 27th, by which time the Moon will be farther out of the way." They're in Virgo about 5½° south of Spica; use a sky-mapping program.

    Tuesday, March 18

  • The bright Moon shines about in line with Saturn and Regulus this evening, as shown below.

  • Algol should be at minimum light for a couple hours centered on 9:25 p.m. Eastern Daylight Time. Best seen from eastern North America.

    Wednesday, March 19

  • Saturn and Regulus shine above the Moon at dusk, as shown below, and to its upper right later in the night.

  • The equinox occurs at 1:48 a.m. Thursday morning EDT, 10:48 p.m. Wednesday evening PDT. This is when the Sun crosses the equator heading north for the year — marking the start of spring in the Northern Hemisphere, and fall in the Southern Hemisphere.

    Thursday, March 20

  • Maybe you already know the big, bright star clusters M37, M36, and M38 in Auriga. But do you know about the six other telescopic clusters nearby? Check out Ken Hewitt-White's "Suburban Star-Hop" column and chart in the March Sky & Telescope, page 55.

    Friday, March 21

  • Full Moon (exact at 2:40 p.m. EDT).

  • A small telescope will always show Titan, Saturn's largest and wildest moon. Tonight Titan is four ring-lengths to Saturn's east. A 6-inch telescope will begin to show the orange color of its atmospheric haze. A guide to identifying all six of Saturn's satellites that are sometimes visible in amateur scopes is in the March Sky & Telescope, page 62.

    Saturday, March 22

  • March is the time of year when the Big Dipper in late evening seems to be pouring into the Little Dipper. Look for the Big Dipper high in the northeast; it's tilting left. The much dimmer Little Dipper extends lower right from Polaris, which is due north.

    On its way to full this week, the Moon passes the Saturn-Regulus pair in the evening sky. (The 10° scale is about the size of your fist held at arm's length.)
    Sky & Telescope diagram

    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 foldout 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).

    Once you get a telescope, to put it to good use you'll need a detailed, large-scale sky atlas (set of maps; 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 enchanting though increasingly dated Burnham's Celestial Handbook). Read how to use them effectively.

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

    This Week's Planet Roundup

    Jupiter on March 2, 2008
    Jupiter is now getting high enough in early dawn to show detail fairly well in a telescope — at least during good seeing. Currently, the North Equatorial Belt (brown band just above center) remains wide and very dark. Can your scope split the thinner, doubled North Temperate Belt just above it? The South Equatorial Belt (just below center) has divided into a dark northern half and a lighter southern half. And the Equatorial Zone, after being remarkably dark last year, has returned to its normal bright state.


    Mike Salway took this image from Australia (where Jupiter rises quite high before dawn) on March 2nd. North is up, and the System II central-meridian longitude was 216°. Little yellow Io is at right (celestial west). The Great Red Spot is on Jupiter's other side.

    Mercury (magnitude +0.0) remains only about 2° from Venus very low before sunrise. It's dozens of times fainter, so bring binoculars. Look for it just to Venus's right early in the week, and to Venus's lower right later in the week.

    Venus (magnitude –3.8, in Aquarius) is getting deeper down into the sunrise every morning. Look for it just above the east-southeast horizon about 20 or 30 minutes before sunup. Binoculars help.

    (To find your local sunrise time, put your location and time zone into 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 +0.5, near the feet of Gemini) shines high in the southwest during evening, high over Orion. In a telescope Mars dwindles from 8.0 to 7.6 arcseconds wide this week — quite tiny.

    Jupiter (magnitude –2.0, in Sagittarius) shines in the southeast before and during dawn. The farther south you live, the higher you'll be able to observe it before dawn gets too bright.

    Saturn on Feb. 23
    Saturn's rings are currently tilted only 8° to our line of sight, as seen in this image taken on the evening of February 23rd when Saturn was at opposition. Two weeks earlier, the outer edge of the rings was sharply outlined by a thin line of their black shadow on the globe, but now the shadow is hidden. Note the dusky C ring just inside the broad, bright B ring. The C ring is obvious as a dark silhouette where it crosses in front of the globe. North is up.
    S&T: Sean Walker
    Saturn (magnitude +0.3, close to Regulus in Leo) glows in the southeast during evening and stands highest in the south around 11 or midnight daylight saving time.

    Fainter Regulus (magnitude +1.4) is now just 4° from Saturn: to its upper right in early evening, and directly right of it later at night. Watch them draw even closer together in the coming weeks. Only a little dimmer than Regulus is Gamma (γ) Leonis (magnitude +2.1), located 8° to Saturn's north.

    Uranus and Neptune are hidden in the glow of dawn.

    Pluto (magnitude 14.0, in northwestern Sagittarius) is well up in the south-southeast before dawn's first light.

    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 (UT, UTC, or GMT) minus 4 hours.

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