You are hereTHIS MONTH’S SKY - March 2012

THIS MONTH’S SKY - March 2012


Celestial Events -- March 2012


All five bright planets will be visible this month in the evening. Four of them will be easy to spot all month long, and the fifth (Mercury) can be seen early in the month. Let's follow a path from west to east.

Mercury takes advantage of the angle of the ecliptic, rising almost straight up from the horizon. On March 1 Mercury's magnitude is -0.7 but it rapidly fades. Look in the first week of the month, when it will be up over an hour after sunset.

You can't miss the next two objects, Venus and Jupiter. As March begins Venus is 11° below Jupiter, but approaches Jupiter quickly. On the 13th Venus passes only 3° above Jupiter. Don't miss this spectacular.

Venus is surrounded by clouds, but in a scope you can see the phases of Venus. During March Venus moves from two-thirds lit to one-half lit. Jupiter is more interesting, with its belts and four bright moons.

Chart 1. Mercury, Venus and Jupiter
in Early March


Chart 2. Close-up.
Venus passes Jupiter


Chart 3. Mars and Saturn

Note Mars's Retrograde Movement


To spot Mars, look head east to the constellation Leo. You won't be fooled by Leo's nearby bright star Regulus, since Mars has a distinctive ruddy color while Regulus is bluish.

Mars is at opposition on the third and brightest two days later.  Earth lies along a straight line between the Sun and Mars. So when the Sun sets, Mars rises. Normally it is difficult to spot features on Mars, even with a telescope. But Mars is close to us now, giving us a rare chance (oppositions only occur every 28 months) to see some detail on Mars, such as its polar ice cap, and dark and light regions.

Saturn is a latecomer, rising in the constellation Virgo at 10 PM. Like Mars, it has a bright star nearby, in this case Spica. Saturn will be at opposition on April 15. Saturn's rings can be seen with a telescope.


Click to get sky charts and a description of the sky for this month.


MERCURY entered the evening sky late in February and is still high up. It is at greatest eastern elongation 18° from the Sun, on March 5. Because of the favorable inclination of the ecliptic, Mercury should be easy to spot the first week of the month, but afterwards quickly plunges back towards the Sun. On the 21st it is inferior conjunction, entering the morning sky, where it will be poorly placed for observing in the Northern Hemisphere.

VENUS (magnitude -4.3 to -4.5, diameter 18.4" to 24.2", illumination 64% to 49%) continues to dominate the western sky. On the 13th it passes Jupiter. The two brilliant objects, the brightest after the Sun and Moon, are only planets are 3° apart and will be a treat to the naked eye or binoculars.. The Moon passes closely below Venus (1.8°) on the 26th. A day later Venus is at greatest eastern elongation from the Sun (46°).

MARS (magnitude -1.2 to -0.7, diameter 13.8" to 12.6"), in Leo, is at opposition from the Sun and up all night on the 3rd.  Two days later it is closest to Earth. (Because Mars' orbit is an ellipse, not a circle, the events don't occur on the same day.)  This is a great time to view the red planet with a telescope.

JUPITER (magnitude -2.2 to -2.1, diameter 36.1" to 33.9") is in Aries. Jupiter spectacularly meets Venus on the 13th (see VENUS above).

SATURN (magnitude +0.4 to +0.3, diameter 18.4" to 19.0") remains in Virgo, near the bright star Spica. It is retrograding in preparation for its opposition from the Sun on April 15.

URANUS (magnitude +5.9, diameter 3.3") is too close to the Sun to be seen. It is in conjunction with the Sun on the 24th.

NEPTUNE (magnitude +8.0 to +7.9, diameter 2.2") is too close to the Sun for most of the month, but can be seen later in the morning sky with a telescope.

PLUTO (magnitude +14.1, diameter 0.1") is in Sagittarius, too near the Sun to be seen.

See below for phases of the Moon and the Moon's conjunctions with planets and bright stars.



(Times in EST until 2 AM March 11, EDT afterwards)

March 5 Mars is closest to Earth
  Mercury is at greatest elongation from the Sun
March 6 The Moon is to the right of the bright star Regulus
March 7 The Moon is lower right of Mars
March 8 Full Moon at 4:39 AM EST
March 10 The Moon is near Saturn and the bright star Spica
March 11 Daylight Saving Time begins at 2 AM
March 14 Last Quarter Moon at 9:25 PM EDT
March 20 Spring begins for the Northern Hemisphere
March 21 Mercury is in inferior conjunction with the Sun
March 22 New Moon at 10:37 AM EDT
March 23 A very thin crescent Moon rises in the west a half hour after sunset
March 24 Uranus is in conjunction with the Sun
March 25 The Moon is only 2⅔° from Jupiter tonight
March 26 The Moon in near Venus (3°) and the Pleiades (6°) tonight
March 27 The Moon is to the right of the bright star Aldebaran
March 30 First Quarter Moon at 3:41 AM EDT