The Sky Tonight is a monthly update of the amazing things you can find when looking up from here in Western Australia. This section is written by Jacquie Milner, resident astronomer at the Scitech Planetarium.
The casual observer
Saturday October 28th has been designated International Observe the Moon Night this year to encourage everyone to appreciate and increase their understanding of our moon. It’s at first quarter, so it will be easy to see in the evening sky. Information on a public activity near you can be found here or just enjoy the Moon from your own backyard.
If you are up in the early hours of the morning around the 21st of the October keep a watch for the Orionid meteor shower. At peak times you may see up to 20 bright meteors an hour streaking quickly through the sky (although it won’t be an even spread, they’re more likely to come in clusters). But this year the Moon is at Last Quarter just a few nights after maximum, making this an favourable year for observing this shower since a bright moon will be flooding the sky with light right where you want to be looking. The meteors that form this shower come from Comet Halley.
Dates of interest
6th – Mars and Venus within 0.2 degrees of each other, dawn sky
18th – slender crescent Moon below Mars and Venus, dawn sky
24th – Moon next Saturn, evening sky
28th – International Observe the Moon Night
Planets to look for
The night skies over the next two months are going to be mostly empty of bright planets. This happens from time to time as they all move in different rhythms and they just happen to be coinciding at the moment.
Jupiter is low in the evening twilight as October begins and quickly sinks out of sight behind the Sun. It is in conjunction with the Sun on the 27th. In the last week of October you may see Mercury in the west instead, but it will be easier to see in November.
Saturn is easiest planet to observe this month. Starting the night high overhead, half-way between Scorpius and the Teapot asterism of Sagittarius, you will have plenty of time to view its rings and moons. The Moon will be next to it on the evening of the 24th of October.
In the morning sky Venus is gradually sinking down into the morning twilight. It has a meeting with Mars, which is now returning to the morning sky, on the 6th of October, when they are only 0.2 of a degree apart. The brightness of Venus should overpower dim Mars. After that date Mars will slowly drift upwards into the darker sky and Venus will continue to sink sunwards.
Constellation of the month
Piscis Austrinis the Southern Fish
Late in the year as you look to the south of where Sagittarius and Scorpius are setting you might notice a couple of bright stars sitting out on their own. The brightest one is called Fomalhaut, which sounds like an odd name, but comes from the Arabic for “mouth of the fish” (fam al-hut.) It does the mark the mouth of a fish, the Southern Fish, Piscis Austrinis, the last of Ptolemy’s ancient 48 constellations, and Fomalhaut marks where the water pouring from the jug of Aquarius ends up – being swallowed by a giant celestial fish! Fomalhaut is the 18th brightest star in the sky.
To north of Piscis Austrinis is Capricorn, and to the south is Grüs the Crane (pronounced “groos”), easily identifiable by the pairs of stairs in his neck and the star Alnair, meaning “The Bright One” on his spread wingtip.
If you’re not sure where Piscis Austrinis might be, look for the curving neck of Grus the Crane to the south of it.
Objects for the small telescope
Messier 6, the Butterfly cluster
Near the sting of Scorpius there are two relatively large open clusters of stars that can be seen. If the sky is dark enough you can even see them with the unaided eye. The larger of the two is known as Messier 7 (or M7 for short) and the smaller one is Messier 6 (M6).
Charles Messier was a French astronomer who lived from 1730 to 1817 and was famous for finding many comets. As he searched the sky he began to make a list of objects he saw again and again that looked like comets but weren’t. We must remember that the telescopes of that time weren’t as big as the ones we use today, or of as good a quality and a lot of things in the sky looked like fuzzy comets! He eventually listed over 100 objects and because they are relatively bright they make a good introduction to what is known as the deep sky to people who a new to using telescopes and are learning to find their way around the night sky.
An open cluster of stars is a loose group of stars that formed together at the same time out of the same cloud of dust and gas. When you look at M6 you see several other open clusters nearby – this is because you are looking towards the centre of our galaxy the Milky Way, where there is a lot of star forming activity. M6 lies about 1600 light years away.
M6 is a cluster of mostly hot blue stars. Look carefully for the butterfly shape – you might need a bit of imagination to see it!
You won’t need much magnification to see this cluster, so give it a go with binoculars, too.
Australia to get a new National Space Agency
Australia was the third country to launch a rocket into space, but it’s been a long time since and many things have changed – most notably a raft of international laws that mean it’s not that easy to do any more. But after some lobbying, and no doubt there was a bit of New Zealand nudging our national pride as they already have a working space agency, it was announced at the 68th International Astronautical Congress in Adelaide on the 25th of September that Australia would get a new National Space Agency.
So does that mean we’ll be in the rocket launching business again? Maybe – and maybe not. Space agencies aren’t all about rockets. There is a lot of other technology that get developed as well, and most of it benefits us on the street. For example, at the moment we get our weather satellite pictures from a Japanese satellite, and that helps us know what’s coming in the next couple of days, we now take GPS finders and locaters for granted in our smart phones which run from US satellites and there are a lot of communications that get routed via satellite as well.
What would happen if another country suddenly decided they didn’t want to share with us? Would we have the capacity to build and launch our own communication satellite? One that improves reception in remote areas? Or one to monitor the weather and sea conditions around our sea-bound continent? What about one to measure soil moisture and crop growth for farmers? There are a lot of possibilities to explore and build on.
Adelaide and Canberra are keen to be space agency centres, and the Northern Territory has an interest, too, being the closest land to the equator in Australia. The closer you can get the equator to launch rockets the less energy you need to launch them – that’s why most rocket launches in the US are from Florida! But we’ll probably have to wait until the next federal budget in May 2018 to find out the details and who gets what honours.