|Events during March
|This month is a planet-gazerīs paradise with all five naked-eye planets on view before midnight
and with Mercury, Venus and Mars each putting on their best evening performance of 2012. Also, this month the nights become shorter than
the days as we reach the Spring Equinox on 20th March, and the Sun climbs over the Equator bringing light and heat to the northern hemisphere.
Even better, the clocks go forward on 25th March so we can longer enjoy warm, balmy evenings.
Look out for Mars at its brightest for the year during early March and for the Venus/Jupiter/Moon configurations towards the end of the month.
During moonless evenings just after mid-month, check out shadows cast by Venus at its most brilliant.
The Spring Equinox, when the Sun rises due east and sets due west, is a good time to mark compass points relative to your home.
3rd- MARS at opposition.
5th - MERCURY at greatest eastern elongation.
5th - MARS closest to Earth.
20th - SPRING EQUINOX, when the Sun crosses the equator into the northern hemisphere.
21st - MERCURY at inferior conjunction.
24th - URANUS in conjunction with the Sun.
25th - CLOCKS GO FORWARD by one hour.
27th - VENUS at greatest eastern elongation.
MOON: Full - 8th, New - 22nd, Perigee - 362,400 kilometres - 10th, Apogee - 405,780 kilometres - 26th.
6th - Moon near Regulus, the brightest star in Leo.
7th/8th - the full Moon passes below Mars.
10th/11th - the Moon lies below Spica (the brightest star in Virgo) and Saturn.
14th - Antares (a red supergiant in Scorpio), is to the right of the Moon in the early hours.
25th - the crescent Moon is just to the right of Jupiter with a brilliant Venus above.
26th - the crescent Moon is just to the left of Venus with Jupiter below.
Mercury reaches greatest eastern elongation
(18š) on 5th March, visible in the western evening sky at the end of twilight for the first two weeks of March for observors in tropical and northern latitudes. For
northern hemisphere observors, this continues to be the most favourable apparition of 2012, fading from magnitude -0.8 to +1.7 after greatest eastern elongation.
Mercuryīs elongation from the Sun rapidly decreases as the planet draws in towards inferior conjunction
on 21st March.
The best times to observe Mercury in the northen hemisphere are when it is an evening star in the spring and a morning star in the autumn. In midsummer
the lighter skies make visibility difficult near the horizon.
Venus reaches greatest eastern elongation
on 27th March. It is a spectacular object in the evening sky at dusk and throughout the evening, brightening from magnitude -4.2 to -4.4 during March as, at the
same time, its phase decreases from 63 to 49 per cent. The planet moves rapidly from
Pisces, through Aries into
Taurus during the month, its northerly declination
allowing it to set more than four hours after the Sun from northern temperate latitudes, although it is visible for less than half this time from the tropics and southerly
Venusīs easterly motion through Aries takes it past Jupiter between the 12th and 15th March and the two planets will make a lovely pairing in the evening
twilight at this time. On 25th and 26th March, the crescent Moon joins the spectacle.
On the 8th June 2004, Venus was at inferior conjunction
and transited the sun. Transits of Venus are rare, taking place at greater
than 100 year intervals and usually in pairs. The last two transits of Venus were in 1874 and 1882. 2004's transit lasted 6 hours, the total event
visible from Europe as a small black disc crossing the lower part of the Sun from left to right. The next transit will be on 5th June 2012.
After that, transits of Venus won't occur again until 2117 and 2125.
Before and after inferior conjuction, when Venus is
the closest it comes to the Earth, are the times at which the planet is most brilliant and can be seen setting or rising
4 hours after or before the Sun.
Mars is at opposition
in Leo on 3rd March, when its magnitude attains -1.2 and the planet is visible all night through. Two days later,
on March 5th, the planet will have its closest approach to Earth during this apparition - 100.78 million kilometres. Mars will be considerably close to
the aphelion of its orbit, which it just passed on February 15th 2012. This opposition occurs close to the northern Summer/southern Winter Solstice on Mars,
which takes place on March 30th 2012, so that Earth will be at high northern declination from Mars, and the Martian North Pole will be in good view from Earth.
Given that this is an aphelic opposition, the apparent diameter of the disc reaches only
13.9 arc seconds - about half the apparent disc diameter enjoyed at a perihelic oppostion
when it can attain 25.1 arc seconds as in 2003 (see below).
Mars will fade quickly after opposition as its distance from Earth increases, its magnitude fading to -0.7 and its apparent diameter to 12.6 arc seconds by the end
of the month.
This opposition provides an opportunity to send further spacecraft to Mars. NASA is sending its Mars lander-rover mission, the Mars
Science Laboratory (MSL, which is also named Curiosity), launched in November 2011. The rover is the size of a Mini-Cooper and is intended
to perform a 2 year science mission on the surface of Mars. This is a sophisticated mission for advanced studies on the Martian surface, including new
technologies - the long-range, long-duration rover, powered by a small nuclear reactor, is equipped to perform many scientific studies of Mars including
the geology, composition and life-potential of the Red Planet, and to demonstrate the technology for accurate landing and hazard avoidance in order to travel to
difficult-to-reach sites. For the first time NASA has admitted the project was designed to look at possibilities of humans going to Mars.
The Russian Space Agency delayed its Phobos-Grunt mission from 2009/2010 to this apparition and is an attempt to return samples from Mars' moon Phobos.
It was launched carrying the Chinese Mars Orbiter Ying Huo 1 on November 8th 2011.
At opposition on the 28th August 2003, Mars was only 56 million kilometres from the Earth. It showed a
disc of 25.1 seconds of arc across which is almost as large as it can ever appear. Mars started 2003 at 310 million kilometres from
the earth at 4.5 seconds of arc and 1.6 magnitude. By opposition it brightened 50 times to reach -2.9 magnitude but faded to 0
magnitude by December. Even to the naked eye Mars was a striking object in the summer and autumn sky, easily identifiable by its
reddish hue in an area of sky poor in bright stars. Mars will not be as close again until 2018.
These favourable oppositions occur every 15 or 17 years but other oppositions occur at average intervals of 2 years 2 months during
which time the planet makes a complete circle of the Earth. In general Mars is observable every other year, being too close to the sun for favourable conditions
during other times. Brightness at opposition varies from -1.0 to -2.9 magnitude, and when furthest from the earth it fades to 1.7 magnitude. The planet can be
identified by its orange-red colour.
As in 2003, Mars comes nearest to the Earth at oppositions at the end of August. At these times it can be brighter than Jupiter,
although low in the sky in Aquarius for northern observors. In the northern hemisphere, the planet may be better seen at oppostions during autumn and winter months
when it is higher in the sky.
Jupiter can be seen in the southern sky as soon as darkness falls, now setting before midnight, with
magnitude decreasing from -2.2 to -2.0 during March. The planet continues to move directly in Aries,
and forms a beautiful configuration with Venus between the 12th and 15th March and with the Moon on 25th and 26th March.
After spending the past six years in the southern skies, Jupiter moved north of the celestial equator on February 5th 2011 to spend the next six years
in northern skies.
Varying from 603 (at its closest) to 770 million kilometres from the sun, the difference in brightness between opposition and conjunction varies less than
with Mars, from about -2.9 to -1.8 magnitude. Always a bright planet, Jupiter comes to opposition a month later each year, moving approximately from one zodiacal
constellation to the next.
The 4 largest of Jupiterīs 60+ moons are easily visible through binoculars or a small telescope, ranging from 4.6 to 5.6 in magnitude. The innermost,
Io, takes 1.8 days to orbit the planet making its motion easily detectable within a few minutes.
Saturn can be seen rising in the eastern sky in mid-evening, moving
retrograde in Virgo. At
opposition next month, magnitude increases from +0.4 to +0.3 during March.
Saturn moves more slowly than Jupiter and can remain in the same constellation for several years. The brightness of the planet depends on the
aspect of its rings, as well as its distance from Earth and the Sun.
The planet crossed the equator into the northern hemisphere in 1996 where it remained until 2010 with the southern side of the ring system
facing Earth. Because of its distance, its brightness varies little between opposition and conjunction but is affected by the huge ring system. Seen edge on the
rings contribute little or no light.
Every 15 years the plane of Saturn's rings passes through the Sun, illuminating first the north and then the south side. For a few days the
rings are edge on to the Sun. About the same time the Earth passes through the ring plane and, depending on the Earth's position, this may happen just once or 3 times.
During 1995/96 there was a triple crossing and the next will be 2038/39. The last single crossing was in 2009 and the next will be in 2025.
Saturn's largest moon, Titan, is visible in small telescopes orbiting outside of the ring system.
Uranus is in opposition on 24th March,
remaining in Pisces with a magnitude of +5.7. Barely visible to the naked eye, it is easily located with binoculars.
Brightness varies only slightly, reaching a maximum of +5.6 magnitude at opposition. Although this is bright enough to see with the naked eye, identifying it against
the stars can be difficult. At closest approach, Uranus is 2,856 million kilometres (1,775 million miles) from Earth.
Neptune has an average magnitude of 7.9 which varies little with changing distance. At its closest,
Neptune is 4,341 million kilometres (2,697 million miles) from Earth.
No longer an offical planet and never brighter than +13 magnitude, Pluto is only visible through powerful telescopes.
First quarter: 1st
Full moon: 8th
Last quarter: 15th
New moon: 22nd
First quarter: 30th