Overview

1st – Venus close to bright star Spica.

5th – Mars to the right of Spica with Venus above.

11th – Moon joins brilliant Venus and Mars in the evening sky.

14th – Moon next to bright star Antares in Scorpius.

23rd – Equinox

  

Moon Phases

New Moon:  8th First Quarter: 15th Full Moon: 23rd Last Quarter:  2nd

 

Planets to look for

Saturn leaves the evening sky this month as it passes behind the sun as seen from the Earth.  After the first week of September it will sink into the evening twilight and become increasingly difficult to see.  It will reappear from the behind the Sun in the morning sky in mid-October.

Above Saturn we have Venus and Mars putting on a show for us as they move together past the bright star Spica in the constellation of Virgo.  Venus will be next to Spica on the 1st of September and Mars moves up next to the star on the 5th.  Watch out for all three with the Moon on the 11th.

On the opposite side of the sky the gas giant Jupiter is rising as the sun sets.  It reaches what is called opposition – when a planet is on the opposite side of the sky to the sun as seen from Earth - on the 21st and the planet will be visible in the sky all night long during the month. 

If you have a telescope you can get an extra bonus this year as you will be able to see Jupiter and the planet Uranus together in the same field of view!  Uranus reaches opposition only five hours after Jupiter this year and should be visible as a pale green dot to the north of Jupiter. They will be within one degree of each other from the 12th to the 25th (that’s about one field of view in the eyepiece at around 50 times magnification).   See our Feature Article for September for more information on this conjunction.

Mercury makes a brief appearance in the morning sky but it doesn’t get very far above the Sun.  If you’re early riser you might catch it between 5.30am to 6am during the middle of the month.

 

 

  

For small telescopes

The Starfish Cluster

To the south of Sagittarius lies the constellation of Pavo the Peacock. 

It’s not an easy constellation to find, with only one bright star but it is worth the effort to search it out for the objects within it. 

It contains a number of galaxies that experienced observers might enjoy but there is also a bright globular star cluster known as the Starfish Cluster that is within easy reach of small telescopes. 

Binocular observers may also pick the location of this object up, but you will need a telescope to see any detail.

Also known as NGC 6752, this globular cluster lies about 15,000 light years away. 

Take a while to look at this cluster – careful inspection should reveal how it gained it’s name.  Imagine a starfish with a small centre and long thin arms curving and curling around it.

 

 

 

 

Featured Constellation

Lyra the Lyre

Lyra is one of the ancient constellations and is said to represent the lyre of Orpheus in Greek mythology. 

A lyre was a stringed instrument, like a small harp but symmetrical in shape, that was said to have been invented by the god Hermes (known to the Romans as Mercury). 

Australians see Lyra in the northern part of the sky, so look northwards about a third of the way up into the sky and you should be able to locate it easily. 

Lyra contains the 5th brightest star in the sky, known today as Vega. 

It was once much closer to the celestial north pole and around 14,000 years ago would have looked as if it was circling around and around the pole in the sky at about 4 degrees distance (about 7 moon-widths). 

Eagles and vultures do much the same in the sky, circling effortlessly in thermals of air, so the meaning of Vega’s name, which is often given as “The Swooping One” or “The Swooping Eagle”, probably originated from this time, although the form of the name we now use comes from the Arabic name for this star, “Al Wega.” 

Because of precession – the wobble in the Earth axis – it is now some distance from the pole. 

Near to Vega is a parallelogram of fainter stars which mark the strings of the Lyre.  If you can find them along with Vega you have the main pattern of this constellation in the sky.

 

  

For Casual Observers

 

The second equinox for 2010 occurs this month on September 23rd.  After this date there is more daylight than night time with the days growing longer as we head towards the summer solstice in December.

There are a number of bright stars visible in the evening sky at this time of year, starting with Vega to the north, and Altair in Aquila the eagle above it. 

Turning eastwards you should notice an orange star looking a little lonely with not many other stars nearby – this Fomalhaut, the mouth of the Southern Fish, Pisces Austrinus.

Lower down, rising out of the south east is Achernar, marking the end of Eridanus the River. 

Seeing that star in the evening once more reminds us that summer is not too far away.

 

 

 

Featured article

Jupiter and Uranus in Conjunction

Jupiter and Uranus can be said to be in conjunction during September in 2010 – that is, they reach their smallest angular separation in the sky as seen from Earth.

   This is actually the second of three meetings this two outer planets will have during this year – there was a conjunction back on June 7th and a third encounter after this one on January 3rd 2011.   Jupiter last met up with Uranus in 1997 and does so every thirteen years.  To make this even more remarkable this time they meet up only a day after they are both at opposition – directly opposite the sun as seen from Earth – so they are visible all night long.

Jupiter is very easy to spot in the evening sky at the moment; it’s the brightest object in the east after sunset.  Uranus is about one degree to the north of Jupiter – that will be to the left for Australian observers as they look eastwards.   If you have binoculars you should be able to spot Uranus, but it will look just like a star.  Observers with telescopes should be able to make out the aqua-green tinge of colour of this gas giant and may even see Uranus presenting as a disc (which means it will look like a small coloured dot, not a pinpoint-like star.) 

For an interesting exercise try drawing their relative positions each night (or whenever you can) and watch them change over a couple of weeks.  You might be surprised how fast they are moving up there!

If you miss this conjunction, remember you’ll have another chance at it in December later this year.