f you're brave enough to venture outside these cold winter nights, you'll be greeted by the heart of our Milky Way galaxy directly overhead. Find yourself a dark space in your backyard on a clear moonless night, and look straight up.

You'll see the unmistakable form of Scorpius, the Scorpion, and the group of stars that make up the constellation of Sagittarius, the Archer. Look carefully in this area of the sky and you'll notice the misty glow of the countless millions of stars that are too far away for us to see clearly. Their light has journeyed for more than thirty thousand years to reach us.

As you scan the Milky Way, you’ll notice vast rifts that don’t seem to contain any stars. These rifts are actually enormous clouds of gas and dust that hide the Milky Way’s stars behind them. It’s not that there are no stars, they are just hidden from our view. The giant clouds of gas and dust will one day condense and form new stars.

Astronauts, looking out of the space station windows at night, see great clusters of lights; the glow of hundreds of thousands of individual lights that mark cities on earth. From the ground, we can see great clusters of lights in the heavens, too; cities of stars we call globular clusters. They're somewhat lost in the background of stars, but binoculars or telescopes reveal their true nature: spherical clumps of thousands or even millions of stars. Our Milky Way galaxy contains a couple of hundred globulars.

The greatest of these is Omega Centauri. Imagine a spherical region of space with our Sun at the centre and the outer edge four light-years away - the same distance as Alpha Centauri, our closest star system. Now imagine that this sphere contained a hundred thousand stars. The night sky would look alive with stars - bright stars in every direction, an overpowering cosmic light show. That's how the sky would appear if the solar system were transported to the centre of Omega Centauri.

You can see Omega Centauri with the naked eye, as a small fuzzy patch in the southwestern sky. It's marked by its catalog number "5139" on this month's star chart. It's visible to the unaided eye, but only binoculars or a telescope reveal its full glory, a dazzling city of stars.
On the opposite side of the sky, high in the northeast, Altair marks the constellation of Aquila, the Eagle. It's flying along the Milky Way towards Cygnus, the Swan, lower in the sky.

Altair is a strange star. It rotates on its axis in just 6 and a half days (the Sun takes 25 days). As a result of this rapid spinning, the star probably has a very flattened shape, the equatorial diameter being nearly twice the polar diameter.
A couple of nearby star clusters are in good view this month. They're high in the sky at nightfall. Both are just above the tip of the curled tail of Scorpius, the scorpion.

The clusters are known as M6 and M7, the sixth and seventh objects in a catalogue compiled by the French astronomer, Charles Messier in the late 18th century. Each cluster is a family. All of its stars were born at the same time, from the same cloud of gas and dust. M7 is perhaps 220 million years old; M6, less than half of that.
M7 stands highest in the sky. M6 is below it. M7 looks bigger and brighter because it's less than half as far away. The cluster is so bright, in fact, that under dark skies it's visible to the unaided eye. It looks like a hazy patch of light with a few stars sprinkled through it. Binoculars reveal many of its stars, while a telescope will show you many more.

On the night of August 6th, look to the northwest soon after sunset and you’ll see the crescent Moon, the brilliant planet Venus and elusive Mercury in a triangle. Make sure you have a clear horizon. The separation between the Moon and Mercury is 7o, so you should just fit all 3 in the field of view of 7x50 binoculars. Scan the line separating night from day on the Moon, you'll see some long shadows stretching across the crescent; shadows cast by the rims of craters, and by lunar mountains.
From these shadows, you might expect the mountains of the Moon to be sharp and jagged, but they're not. The mountains are gentle and rounded.

Sharp, jagged mountains here on Earth are young and fresh. Over time, though, they are eroded by wind and rain, chipping off tiny bits of rock that wash down the sides. Over hundreds of millions of years, rugged mountains, like the Himalayas, are turned into rounded mounds, like the Mount Lofty Ranges.

So, the mountains of the Moon must be old and eroded, too. But there's no air, water, or life on the Moon, so they're eroded by a different source - meteorites. Particles of rock scattered throughout the solar system rain down on the lunar surface, chipping away at the mountains. Most of the meteorites are no bigger than grains of sand. Since most of the lunar mountains formed more than three billion years ago, there's been plenty of time to wear them down; forming gentle, rolling hills on the surface of the Moon.

Venus looks like a dazzling star just below and to the left of the Moon. Venus is the second planet out from the Sun, while Earth is third. Because of that, Venus has a limited range in our sky. At best, it’s visible for a few hours before sunrise or after sunset. Also because of that arrangement, Venus shows phases, just as the Moon does — from a bare crescent to almost full. It’s a crescent around the time it passes between Earth and Sun, and almost full just before it passes behind the Sun. We don’t see it when it’s full because it’s too close to the Sun then.

Right now, the planet is showing almost a full phase. You might expect the planet to be brightest when it’s full, and faintest when it’s a crescent, but that’s not so. Venus is much closer to us when it’s a crescent, so it covers a larger fraction of the sky. We also catch more of its reflected sunlight then. So, Venus is at its brilliant best a little before and after it passes between Earth and the Sun. At the moment, it’s just emerged from the other side of the Sun, so it’s a whopping 242 million kilometres away.

The Moon is New on August 4th, at First Quarter on the 13th, Full on the 20th, and at Last Quarter on the 26th of August.
Happy stargazing!!