At the beginning of March look west just after sunset to see three of the ‘wandering stars’.  Mercury will be close to the horizon, with Venus and Jupiter shining brightly above it. Mercury will quickly set below the horizon and by the middle of the month will have disappeared from view. Venus and Jupiter have been drifting towards each other for some time now and will finally pass each other like ships in the night on 12 and 13 March. They will be about three degrees apart, with Venus at magnitude -4.3 and Jupiter a little fainter at magnitude -2.1. In the second half of the month Venus will  rise higher in the sky while Jupiter will continue its descent towards the horizon.

image of Jupiter Venus Mercury

You could almost draw an imaginary line through Jupiter, Venus and Mercury. But hurry to catch these three planetary siblings before Mercury goes to bed. Image Credit Mary Bulman/Stellarium/Armagh Planetarium)


Not to be outdone the eastern sky also has some planetary activity but you have to wait till it gets a little later. Mars, the Red Planet can be spotted under the belly of the Leo, the majestic celestial lion who was defeated by Hercules in a wrestling match. Saturn, famous for its spectacular rings, is just to the right of Spica, the brightest star in the constellation of Virgo. So this month all the planets that are visible to the naked eye are on view in the heavens. You don’t need a telescope or binoculars, just your own little eyes. And the best part is that this is a free show. There are few free shows to be had in life except at Armagh Planetarium on 10 and 11 March when Titan the Robot stomps through our doors!


image of saturn in virgo

Leo is rising high in the east, a sure sigh that spring has arrived. ( Image credit: Mary Bulman/Stellarium/Armagh Planetarium)


Staying in the east, Leo the Lion is easily identified. Its brightest star is Regulus, the “little king”. Regulus is the bottom star in a pattern that looks like a backwards question mark; this asterism is called the Sickle and forms the head of the mighty celestial lion.  Regulus is one of the four Royal Stars of the ancient Persians. The other three are Aldebaran, Antares and Fomalhaut.  These stars are situated about 90 degrees apart in the sky so a prince (or princess) could always claim to be born under one of them. A very convenient system!

If you are a Harry Potter fan you will be familiar with the character Regulus Arcturus Black (1961 – 1979) also known as R.A.B, a pure-blood wizard who was the younger brother of Sirius Black.  .

Leaving the realm of fiction and moving on to some facts. Regulus is a 1.4 magnitude blue-white class B7 star. It is five times the diameter of our Sun and about 150 times more luminous.  Regulus is estimated to be about 77 light years from us which means that the light you see when you cast your gaze on this twinkler left it in 1935 back when Cats’s Eyes and the 30mph speed limit arrived on UK roads, Porky Pig made his screen debut, Elvis Presley was born and it was starting to look as though that Hitler chap might be a bit of a trouble maker.


image of The Winter Circle

On a clear night these beautiful, bright stars of the Winter Circle are a joy to behold. (Image Credit: Mary Bulman/Stellarium/Armagh Planetarium)


There is a profusion of bright stars on display at the moment, the most notable of which are known as the Winter Circle. This asterism of seven bright stars forms a rough celestial circle. There is a bonus bright star inside the circle. All the stars are between magnitude 1.1 and -1.4.

To find the Winter Circle first locate Orion. Starting at Orion’s foot is the bluish star Rigel, which at magnitude 0.1 is the seventh brightest star in the sky. Moving clockwise the next member of the circle is the brightest star in the night sky, Sirius, the Dog Star, shining at magnitude -1.4 in Canis Major. Continuing clockwise and moving up in the sky, in Canis Minor, we find Procyon, the eighth brightest star in the sky which is shining at magnitude 0.4. The constellation of Gemini provides two of the stars to the circle.  The twins’ heads, Castor and Pollux which at magnitude 1.1 is the 17th brightest in the sky and dimmest in the circle

Continuing clockwise, Capella in the constellation Auriga, is the highest star in the circle. It shines at magnitude 0.1and is the sixth brightest star in the sky. Now curve back down toward Rigel and you will come to a reddish star. This is Aldebaran, the fiery eye of Taurus the ferocious bull. At magnitude 0.8 Aldebaran is the 14th brightest star in the sky. The bonus star is Betelgeuse which marks the shoulder of Orion. At magnitude 0.5, it is the10th brightest in the sky. Betelgeuse along with Sirius and Procyon form an asterism known as the Winter Triangle. Happy hunting, these are easy to spot. Really.

March hosts the astronomical event known as the Spring equinox. The Spring or Vernal equinox occurs on 20 March (at 5. 14 am UT to be precise) and marks the beginning of spring in the northern hemisphere and autumn in the southern hemisphere. On this day the Sun will shine directly on the equator and there will be nearly equal amounts of day and night throughout the world. The word equinox comes from the Latin aequus (equal) and nox (night), because at the equinoxes (March and September) night and day are roughly equal.

Many cultures and religions celebrate or observe holidays and festivals around the time of the March equinox. In the Christian tradition the date of Easter is associated with the spring equinox, reflecting the close connection between Judaism and Christianity.

Jesus’ death and resurrection occurred around the time of the Jewish Passover, which was celebrated on the first full moon following the vernal equinox. In the early church Easter was being celebrated on different dates by various Christian groups until 325 BC when the Council of Nicaea decreed that Easter would be held on the first Sunday after the first full moon occurring on or after the vernal equinox. Easter is delayed one week if the full moon is on Sunday, which decreases the chances of it falling on the same day as the Jewish Passover.

In Iran the New Year begins on the day when the March equinox occurs before apparent noon (the midpoint of the day, sundial time, not clock time) in Tehran. The start of the New Year is postponed to the next day if the equinox is after noon. The Iranian New Year is known as Nowruz and has many customs associated with it.

The celebrations, which are of 12 days duration date back to pre-Islamic times. Preparations begin in plenty of time and include getting new clothes for all family and a big spring clean of the house.

It is an ancient Chinese custom to balance eggs – a symbol of fertility – on the day of the March equinox to bring good luck and prosperity. The spring equinox is also an important time for pagans who associate this time with fertility and rebirth.

(Article by Mary Bulman, Education Support Officer)

1 Comment

Neil · March 19, 2012 at 21:51

Was taking photographs of Venus & Jupiter yesterday evening (18 March 2012) approx 9.00pm and the photos show a greenish light near Venus, which is in different positions in each shot but does not track across the sky.

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