May 2018

Planets to look for

Have you seen Venus yet, low in the evening twilight? It will soon be a regular feature of our evening skies in the north-west just after sunset. But all the other planet action is in the opposite side of the sky at the moment, so once you’ve dazzled by the brilliance of Venus, turn around to look east.

Jupiter reaches opposition (opposite the Sun from the Earth) on the 9^th of May, so is also looking its best for the year during May. You really can’t miss it – it out-shines all the stars in the evening sky to the east at the moment.

Saturn and Mars are not as bright, but once you have them located they should also stand out. Saturn is still near the Teapot asterism of Sagittarius, and the waning Moon will be next to it on the evening of the 4^th of May. Mars rises about an hour after Saturn now, and the Moon will be under it a couple of nights later on the 6^th. It will end the month near the top of Capricorn.

Mercury is easily visible before the morning twilight starts for the first two weeks of May, then it heads down towards the Sun, finishing the best morning apparition of the year for the southern hemisphere. It will be largely hidden behind the Sun during June. There is a last chance to see it with the Moon in the morning sky on the 14^th of May.

Constellation of the month

Crux, better known as the Southern Cross, is high in the early evening sky at this time of year. Because it’s so eye catching, most people forget about the constellations around it. Crux is surrounding on three sides by Centaurus, an old and very large constellation. But below it lies a small constellation that could be seen to have a close connection to the Southern Cross here in Australia.

Musca the Fly was originally known as Apis the Bee. It was created by two Dutch navigators in the late 16th century.  The French astronomer Lacaille renamed it in 1752 and that is how it has been known since.  It doesn’t really look like the common blowfly that we know so well here in Australia, but if you turn it upside down you can see the wings extending out from it long body.

As the Southern Cross climbs higher into the evening sky, so does Centaurus, the large constellation that surrounds it on three sides. Centaurus contains a number of good objects to see, such as alpha Centauri, the closest star outside of our solar system, and omega Centauri, a huge spectacular globular cluster of stars. Just above omega is a galaxy whose mysteries have gradually been revealed over recent years.

Commonly known as Centaurus A, as it is a strong source of radio emissions in Centaurus, you might also find it marked on charts as NGC 5128.  It is part of our local group of galaxies, lying only 14 million light years away.

Photographs of this galaxy show a thick band of dust circling around it across the middle.  This band of dust is easy to see even in binoculars.  It appears to cut the galaxy in half, which has led some people to nickname it the Hamburger galaxy.

The dust hides a lurking monster – a super massive black hole lies in the heart of this galaxy, the source of the strong radio waves and x-rays.

You will need to be a dark place with no moon in the sky to see Centaurus A (see the Moon Phases on these pages to check when might be the best time this month).  Light pollution, both man-made and natural, will just wash this galaxy away.

To find it, locate the Pointers to the Southern Cross, alpha and beta Centauri.  Beta Centauri is also known as Hadar.  Move up to epsilon Centauri and then keep going in the same line to the spectacular sight of Omega Centauri.  If you keep moving in the same direction, along that line made by Hadar, epsilon and omega, you should find Centaurus A about the same distance from omega as omega is from epsilon. (See finder chart below)

The good thing about this galaxy is that if you can get away to a dark place on a moonless night, you can actually spy this galaxy in binoculars. And some people have even seen it with the unaided eye under the right conditions. Now there’s a challenge!

Star hop your way from Hadar to epsilon Centauri, then the big globular cluster omega Centauri before the last jump up to Centaurus A.

Launch Window for Mars InSight opens

There is an opposition of Mars this year, so that means there is a launch window for missions heading to Mars opening up. The first mission to head off is likely to be the Mars InSight mission, involving a lander and two cubesats, called MarCO, due to arrive in late November, if all goes well.

What is a cubesat? Perhaps you’ve heard the term recently; they’ve become quite popular! A cubesat is a satellite unit no bigger that 10cm-cubed. You can join cubes to increase functionality, and the MarCO cubesats will have six cubesats joined together.

On May 5^th, if all goes well, Mars InSight will be the first interplanetary launch from the west coast of the US, at the Vandenberg Airforce Base, California, and not from Cape Canaveral in Florida, where we are used to seeing launches from. It will spend around six months travelling to Mars and will land on the red planet on November 27^th, with the two MarCO cubesats relaying data about the landing back through deep space.

Once deployed on the surface on the Elysium Plantia, not far to the north of the Curiosity Rover, the Insight lander will have two main goals: To study the interior structure of Mars and to monitor the current tectonic activity of Mars and how often it is hit by meteorites.

For more information and pictures about this mission, visit the official webpage at https://mars.nasa.gov/insight/

An artist’s impression of what the Insight lander might look like once it has deployed on the surface of Mars. Credit: NASA/JPL-Caltech