All the stars we see in the night sky belong to our Milky Way galaxy. However, there are some objects outside of the Milky Way galaxy that can be seen quite clearly with no or little optical power.

Look high in the southern sky in the mid-evening. Make sure you are in a dark part of the garden, or even better, under a dark country sky. Approximately half-way between Achernar and the horizon, you will see what looks like a faint cloud. Higher and to the right is a smaller cloud. Known as the Large and Small Magellanic Clouds, they were first sighted by Portuguese explorers when they sailed into southern waters in the 15th century. They saw two small, fuzzy blobs in the heavens, faintly glowing clouds that weren't visible from their homeland. They were soon named for Ferdinand Magellan, the explorer who organized the first trip around the world.

But it was not until well into the 20th century that astronomers understood the true nature of the Magellanic Clouds. They are small galaxies containing a few billion stars. The Large Magellanic Cloud is the closer of the two, at a distance of about 170,000 light-years, whilst the Small Magellanic Cloud is about 210,000 light-years away. Both clouds are satellites of our own Milky Way galaxy, and even interact with the Milky Way. Interact is too gentle a word. Let us say it like it really is – the Milky Way galaxy is cannibalising these 2 smaller galaxies. Astronomers have detected streams of stars and gas that are being drawn into our galaxy. In about 2.7 billion years, both of the smaller galaxies will have been entirely absorbed by our hungry monster.

The summer Milky Way rises in the east in the evening. It brings with it sparkling stars like Sirius, Rigel, Betelguese, Aldebaran, Canopus, Achernar and Procyon, providing a formidable brilliance to the eastern sky which is not repeated at any other time of the year.
Of course, December is Christmas month, and if Santa is especially generous this year, you might find something shiny in your Christmas stocking: gold. As you admire it, think about this: that bit of soft, beautiful metal just might have been created during the birth of a black hole.
If gold doesn’t feature on Christmas morning, perhaps a pair of binoculars will. These are a great way to develop your interest in astronomy. They will allow you to see many more stars, the craters on the Moon, the phases of Venus, the moons of Jupiter and many more of the vistas in our night sky. And what better target, than a group of stars known as the Pleiades.
Probably better known by its more common name of “the Seven Sisters”, the cluster marks the shoulder of Taurus, the bull. You can find it low in the north-eastern sky by 10:00pm in early December.

The Pleiades is a cluster of several hundred young stars, 400 light years from Earth, and no more than 6 million years old. Our Sun is a middle-aged star, at an age of approximately 4,500 million years old. If we were orbiting a star embedded in the Pleiades, and looking back toward our own solar system, the Sun would be invisible. It is just too faint to see from that far away. But many of the stars of the Pleiades are hotter and brighter than the Sun, so they are easy to see.

Because they occupy an area of sky larger than the full moon, binoculars offer the best method of viewing these stellar siblings. Whilst seven is the number of stars you should be able to see with the naked eye under dark conditions, your view in binoculars will be rewarded by a sight of some 45 to 50 brilliant stars shining against the blackness of space.

With the multitude of bright stars in the summer sky, none is more brilliant than Sirius, shining brightly, low in the eastern sky. This is the brightest star in the whole sky. Sirius looks so bright for a couple of reasons. First, it IS bright; it produces about 30 times more energy than the Sun. And second, Sirius is a mere nine light-years away. Only a handful of stars are closer than Sirius. Viewed through binoculars in a dark sky, Sirius is a breathtaking sight, sparkling with the fire of a brilliant diamond.

Sirius is actually a binary system; two stars that move through space together, bound by their mutual gravitational pull. The star that we see with the unaided eye is called Sirius A. The other star is Sirius B. Since Sirius is known as the "dog star," Sirius B is nicknamed "the Pup." The two stars orbit each other once every 50 years.

Sirius A is a "main-sequence" star. That means that like our Sun, Sirius is in the prime of life. It's "burning" the hydrogen in its core to make helium, releasing energy in the process. But Sirius A is about twice as heavy as the Sun, so its nuclear furnace burns hotter and faster than the Sun's. As a result, Sirius A will live a shorter life.

Sirius B is a white dwarf; the burned-out core of a star that's at the end of its life. It shines only by releasing the intense heat it built up during hundreds of millions of years of life. It's so small, and so close to Sirius A, that you need a large telescope to see it. It has consumed its nuclear fuel and collapsed into a ball no bigger than Earth. Yet Sirius B is as massive as the Sun, so it's extremely dense.

The same fate awaits the Sun in about five billion years. Sirius A will become a white dwarf, too, although much quicker than the Sun will. So, by studying the Sirius system, astronomers get a high-speed look at how the Sun will age, and a preview of our star's fate.

To the north of Sirius, another bright star beckons us. This is Rigel, which at 900 light years away, is more than 100 times further away than Sirius. Yet, if we swapped the two, then Rigel would shine so bright that it would produce about a fifth the light of the full moon. Rigel is the brighter of the two stars. Sirius appears brighter because it is so much closer.

The Southern Cross and the Pointers are skimming the southern horizon and will not be well placed for easy evening observation until early February next year.

Of course, the story of the Star of Bethlehem is always mentioned at this time of the year. A planetary grouping is sometimes cited as a possible explanation for the Star of Bethlehem. Have you ever ventured outside on Christmas night, as I have, gazed up at a starry sky, and wondered about the truth of this story? Using readily available computer programs, you too can simulate the night sky over Bethlehem at the birth of Christ.

The planetary grouping of June 17, 1 BCE figures high on my list of probable explanations for the Star of Bethlehem, and features Jupiter and Venus. On that evening, they came within 30 arcseconds of each other. This is such a minuscule distance that, to the naked eye, the planets would have appeared as a single dazzling star. The conjunction would have been visible after sunset in the western sky, setting out of sight about two hours later. The only drawback with this explanation is that the Wise Men reported first seeing the star "in the east". Could the combined brightness of these two planets have rendered them visible in daylight? I think so! They would have risen in the east about 8.00am local time.

The Moon is Full on December 5, at Last Quarter on December 12, New on December 20 and at First Quarter on December 28.

Happy observing!

Above: The view, looking West, just after sunset on 17 June, 1 BCE, with Jupiter and Venus separated by only 30 arc-seconds. They would have looked like a single, very bright star. (Generated with Stellarium software, v25.3)