The Night Sky in May 2006

Looking at the night sky with the naked eye or using a small telescope can be fascinating, so each month these notes keep you up-to-date with unfolding events.

Maps of the current night sky can be seen by clicking HERE

Phases of the Moon in May


New Moon Saturday 27	First quarter Friday 5	Full Moon Saturday 13	Last quarter Saturday 20

Click HERE to see the phase of the Moon on each day of the month.

Monthly Highlights

Although a little later than previous years, spring finally seems to be upon us and the coutryside is turning lush shade of green as it basks in the warmth of the Sun. The longer days mean that it's nearly 9pm before the Sun goes down, and a good hour later until the sky is dark enough to look clearly at the night sky. If you do get to stay up later than that, then you may be able to spot one of the following monthly highlights:

May 12th - Comet 73P Schwassmann-Wachmann 3

This month heralds the arrival of a new cosmic visitor to Earth's neighbourhood, in the form of Comet 73P Schwassman-Wachmann 3 (SW3). The comet was discovered by German astronomers Arnold Schwassmann and Arno Arthur Wachmann back in 1930 while hunting for asteroids. Despite its relatively short orbital period of 5.4 years, the icy object was not seen again until 1979, and then was missed during a 1985 pass. Since then, however, astronomers have kept a close eye on Comet SW3 and in 1995 observed the remarkable spectacle of it slowly breaking up into many fragments, which at last count numbered close to 40 pieces.

Images of fragments of Comet SW3 which broke up in 1995 - ©NASA

Comet SW3 is interesting because it will pass very close to Earth in the coming month; so close in fact that it started some rumours that one of its fragments might even hit the Earth. However, NASA scientists are happy to confirm that no part of the comet will come any closer than 8.8 million kilometers (5.5 million miles) from Earth. That's a distance of more than 20 times that to the Moon.

Finding chart for Comet SW3 fragments - ©Stellarium

The closest approach of all fragments will take place between the 12th and the end of May, with the main chunk, Fragment C, passing Earth on the 12th May at a safe distance of 11.7 million kilometers (7.3 million miles). Skywatchers will be able to spot chunks of the comet by using a small telescopes to scan near the constellation of Cygnus during the early hours of the morning - see finding chart above.

If you want to learn more about Comet 73P Schwassman-Wachmann 3, click on this link.

The Planets

Click HERE and start the Electric Orrery to see where all the planets are today in relation to each other.

Mercury

Mercury starts the month as a morning object, rising just 15 minutes before the Sun. This makes it hard to see due to the solar glare. Having spent most of April between us and the Sun, Mercury is now preparing to pass behind the Sun and will reach superior conjunction (on the other side of the Sun to the Earth) on the 18th May. Mercury will then revert to an evening 'star', although it will only be visible again toward the end of the month, when it will disappear 30 minutes after sunset. Unfortunately, because Mercury is always low when the Sun is about, it is one of those objects that the Liverpool telescope cannot safely observe.

Venus

Venus continues to move away from us on the inside track and will remain a morning object and brightest planet for most of 2006, finally passing behind the Sun in late October. Having reached greatest elongation (separation from the Sun) in late March, early birds can spot Venus around 70 minutes before sunrise. Why not use the electric orrery to see how Venus remains a morning object over the next few months.

Mars

Mars remains visible throughout the month but continues to diminish in size and brightness as Earth moves away. It can be found high above the western horizon shortly after sunset and spends half the night crossing the sky until it sets in the northwest around 1am. This moves closer to midnight by the end of the month. Now only slightly brighter than stars around it, Mars will be noticeable only by its slightly red hue and the fact that it moves from night to night. We can still observe Mars using the Liverpool telescope, but sadly it will be another 18 months before we get really detailed images again.

Jupiter

Jupiter remains the best target to observe as it passes opposition (the other side of Earth to the Sun) on the 4th May. This majestic gas-giant planet can be found above the southern horizon close to midnight and will remain at its brightest throughout the month, albeit still 5 times dimmer than Venus. Because of the short nights at this time of year, Jupiter rises and sets during daylight. Why not use Go Observing to obtain an image of Jupiter and see if you can capture its elusive red spot, which is still on show at the moment.

Saturn

Saturn continues to decrease in size and brightness as we move slowly away. At the start of May, it can be found high to the west-southwest shortly after sunset and spends the night crossing the sky before setting in the northwest around 2.30am. This moves back to 1am by the end of the month. Saturn is now on the limit of being a suitable target for the Liverpool telescope, but beyond the end of this month, you would be better off waiting until the end of this year, after we have passed around the back of the Sun.

Constellation of the month

Each month, new constellations are highlighted for you to identify in the night sky.

This month we will be looking for the winter constellation of Virgo, the Maiden. Virgo is the second largest constellation in the sky after Hydra, and is dominated by a single bright blue-white star called Spica, which is just 260 light years away. Virgo can be found above the southern horizon close to midnight, just above and to the right of the planet Jupiter, which continues to shine bright and steady. Good hunting!

May Night Sky

The constellation of Virgo is famous for a spectacular supercluster of galaxies, located on its northern border. The Virgo supercluster contains over a thousand galaxies of all different shapes and sizes, with each galaxy containing hundreds of millions of stars. The brightest galaxies can be seen with small telescopes as faintly glowing patches of light. The centre of the supercluster is about 65 million light years away.

Galaxies are held together in clusters by gravity, which pulls them towards each other in the same way that clusters of stars can form. Our very own Milky Way galaxy is part of the Local Group cluster of galaxies, which itself is a distant part of the Virgo supercluster.

Mythology: Virgo

The constellation was named for the Greek goddess Demeter, the Earth-goddess, and is associated with the arrival of spring and bringer of the growing season. Hades, the God of the Underground, fell in love with Demeter's daughter, Persephone. He promised himself that he would marry Persephone, making her his queen. One day Hades, in a black chariot drawn by four great black horses, rode up to Persephone and carried her off to the Underworld.

Demeter became worried when her daughter did not return home and started searching for her, without taking food or sleep. Because Demeter was distracted, people everywhere were starving and could not understand how their Earth-goddess could be so cruel. Zeus sent Hermes, Messenger of the gods, to bring Persephone back from Hades, but on her return she declared her love for her husband Hades. Zeus arranged that that Persephone would spend half of her time in the Underworld with Hades and the other half on Olympus with her mother.

In this way, winter comes when Persephone goes down to the Underworld to be with Hades. When she returns to Olympus, the winter ends and there is a rebirth of life over the land and the crops begin to grow.