Focus on Saturn this month
In July, we have our coldest nights, however with the cold comes the clear. The frosty weather provides us with the clearest skies of any time of the year, which allows us a chance to see objects in the night sky with clarity, both near and far.
Brave the cold this month and you will see the bright winter Milky Way stretching overhead. Being away from the city we can see it very clearly. Pick a moonless night and take a look yourself.
Astronomers travel from all over the world, coming to Australia to see the Milky Way at this time of the year. Our latitude provides us an excellent view. All we have to do is go outside and look.
Bright stars this month include orange Arcturus towards the north, blue-white Canopus low in the south west, yellow Alpha centauri overhead, red Antares close to Mars and Saturn, and white Altair, a star of spring, rising low in the east.
Chart (9pm on the 15th July) produced using the Stellarium software package
Jupiter and Mars bright, Saturn at its best
Three bright planets grace our skies during July: Jupiter, Mars and Saturn. Jupiter can be seen shining as a bright steady yellowish ‘star’ low in the north west after sunset, in the constellation Leo.
Jupiter has been visible in our evening skies for some months now, and is moving closer to the Sun as seen from Earth. It will move behind the Sun in September, after which it becomes visible in the early morning sky.
Jupiter still shows a wealth of detail when seen through a telescope, most conspicuous being the main cloud bands and patterns, along with it’s four biggest moons. Jupiter is an impressive sight at any time through a small backyard telescope. Take this opportunity to have a look. Binoculars will reveal Jupiter’s four biggest moons.
The second bright planet seen this month is Mars, the red planet, which was seen at its best back in May. It still shines brightly as a reddish ‘star’ near the (also red) star Antares.
Mars is now drawing away from the Earth and becoming smaller and fainter in our skies, but July still gives us a chance to see the polar ice caps, clouds and dark surface markings of that frozen desert world. Mars will continue to be visible for some months to come, albeit becoming fainter as each month goes by.
Close to Mars and Antares is the planetary highlight for July, the ringed planet Saturn. It was closest to Earth last month, but is still a very impressive sight when seen through a backyard telescope.
Accompanying this article is a picture of Saturn taken from Bungendore on the 15th June. It shows the main features that can be seen with a small telescope, namely Saturn’s magnificent ring system, as well as the yellowish colour of the planet and the reddish-brown cloud bands that occur there. There is a semi-transparent ring close to the planet (called the ‘crepe’ ring) which is also visible.
The picture also shows a big gap in the ring that goes all the way around called the ‘Cassini Division’. This is a clearing in the ring caused by the gravity of Mimas, one of Saturn’s tiny moons, which sweeps out the ring particles from that part of the ring every time Mimas orbits around the giant planet. The Cassini Division is 4,800km wide, about the size of the Atlantic Ocean, measured between Europe and the USA.
The Earth itself is about the same size as the ‘A’ ring, the part of the ring outside the Cassini Division, which looks a darker grey than the inner part of the ring.The south pole of Saturn can be seen peeking through the Cassini Division right at the bottom.
You will need a telescope to see Saturn’s rings, it is too far for them to be seen through binoculars, but if you have one, take this opoprtunity to see them for yourself.
In July, the Moon is new on the 5th July, at first quarter phase on the 12th, full on the 20th and at last quarter phase on the 27th.