Most people will have heard the term “constellation” and will know that it relates to patterns of stars in the sky.

Many people will probably think of astrology and the “Signs of the Zodiac”, for example Aquarius and Pisces.

But how many people know what the constellations actually are?

The star constellations are really just a fairly arbitrary way of dividing up the night sky, in a memorable way.

But arbitrary or not, the constellations are very useful and help observers to find their way around.

Dividing the sky up in this way, probably started as long ago as humankind itself.

Early people certainly drew recognisable shapes representing star patterns and also began to associate these shapes, with Gods or important legends and stories.

The constellations became somewhat more precisely defined with the early Greek astronomers, who classified a total of 48 star patterns.

At this time, the notion of the “Zodiac” stars also began. The Zodiac is the 12 star patterns or constellations, that the Sun appears to pass through, during the 12 months of the Earth year.

Hence the idea of each constellation being associated with a specific month of the year.

Interestingly, there should probably be thirteen signs in the Zodiac, because the Sun does actually pass through the constellation of Ophiuchus, as it is now defined!

There is one very important point to make about the constellations. Each constellation is not a real grouping of stars – it is only the appearance of a group, from our viewpoint here on Earth.

In fact, the stars in any particular constellation are at greatly different distances from Earth. So if we were to see them from a different position in our galaxy, they would not look like a group at all.

The constellations as astronomers know them today, were defined properly in the 1930′s, by the International Astronomical Union (IAU).

There are now 88 constellations. They vary in size, but generally, each constellation extends beyond the recognisable pattern of naked-eye stars (called an asterism) into the surrounding sky.

So for example, the constellation of Ursa Major contains the highly recognisable shape of the “Plough” or the “Big Dipper”. This is called an asterism.

The Plough asterism is made up of seven stars that appear bright to us on Earth. But the constellation of Ursa Major is much larger and contains many, many more stars and indeed other galaxies, that we can observe.

Taken together, the 88 constellations map out the entire sky into 88 areas. This is very useful to astronomers, when they want to describe where an object may be observed.

In August 2008, NASA confirmed water on the planet Mars.

They have analysed Martian soil samples gathered by the Pheonix lander, from the surface of Mars.

How is this done from so far away, you may wonder?

Astonishingly, Pheonix has a robotic arm. It is able to reach out and scoop red soil from the Martian surface, into the spacecraft’s body. There, the soil is heated and the vapours analysed.

Water has been confirmed. It has been suspected for centuries, but only now “touched and tasted” in the words of the scientists involved.

The question of water on Mars, became a full-blown controversy in the late 1800′s.

Leading astronomers notably Percival Lowell, claimed to have observed networks of “canals”, through telescopes. Previously, they had been suggested by Shiaparelli and termed “canali”.

Quickly, it was speculated they were the work of intelligent beings – hence the notion of “Life on Mars”. Water is a prerequisite for life as we know it.

In 1898, the publication of H G Wells’ famous novel “The War of the Worlds”, added populist fuel to the debate.

Perhaps this latest discovery from NASA of water evidence, will rekindle the speculation? I’m sure, further work is needed for any proof.

In mythology, Orion is said to be a hunter. The shape of the stars in the sky can be interpreted as a man, with a belt and sword, who is holding out a shield against the neighbouring constellation of Taurus, the Bull.

Constellation of Orion

However, from northerly latitudes in Summer, Orion is below the horizon at night and cannot be seen.

The main and easily recognised star pattern within Orion, is four stars in a rectangle which is bisected by the slanted “belt” of three stars.

In one direction, the belt points to Sirius, which is the brighest star in the sky and in the constellation of Canis Major. In the other direction, the belt points to the orange-red star Aldebaran in Taurus.

Orion is therefore a very useful “signpost” in the sky.

The “sword” of Orion, which appears to hang down from the belt, is actually a huge nebula (M42/M43), where stars are being created.

Each of the four main stars are bright and interesting.

Betelgeuse

The top left star (for an observer in the northern hemisphere) is the brightest. It is alpha-Orionis, called Betelgeuse.

Betelgeuse is noticably red-coloured to the unaided eye and is a red super-giant, variable star.

Its magnitude fluctuates between O and 1.3 every 6 years and it also pulsates in diameter from 300-400 times the size of the Sun. It is a true giant and it is 430 light years away.

Rigel

The bottom right star is Rigel and it is usually the brightest in Orion at magnitude 0.2. However, because of Betelgeuse’s variability, Rigel is designated beta-Orionis (not alpha-Orionis).

Rigel is a blue-white supergiant that is 800 light years away so it is nearly twice as far from Earth as Betelgeuse.

Bellatrix

The star at the top right (for Northern hemisphere observers) is a gamma-Orionis, called Bellatrix. It is a blue giant of magnitude 1.6

Saiph

The bottom-left star is Saiph, kappa-Orionis, at magnitude 2

The “Belt” of Orion

In some ways, the three stars which form the “belt” are the most interesting.

From left to right, they are zeta-Orionis called Alnitak (“the girdle”), then epsilon-Orionis called Alnilam (“string of pearls”), and lastly delta-Orionis called Mintaka (“belt”).

Alnilam is a blue super-giant, magnitude 1.7. It is 1600 light years away.

Both Mintaka and Alnitak are multiple stars.

Mintaka is an eclipsing binary with a period of 6 days. The pair is a magnitude 2.2-2.35 blue-white star with a magnitude 6 companion you can see in binoculars and small telescopes.

Alnitak is a tight pair of stars with magnitude 1.8 and 4. You need a good telescope to split them.

Sigma-Orionis

Just below Alnitak, is another multiple star, sigma-Orionis. It looks like a double star in binoculars, but a decent small telescope will actually show it to be four stars.

The “Sword”

As mentioned above, the Sword can be seen just under the belt.

It is a swirling mass of gas called the Orion Nebula, where stars are being born and it is excellent to observe through binoculars or telescope.

When Messier compiled his famous catalogue, he recorded this gas cloud as two separate objects, M42 and M43. Astronomers now believe them both to be part of the same cloud, although there is a dark area which makes them look separate, through a small telescope.

The “Trapezium”

In the centre of the Orion Nebula is the multiple star, theta-Orionis. Through a telescope, you can see a trapezium pattern of four stars.

It is believed that these stars have actually been created from the cloud of gas that is the Orion Nebula and that it is their light, that makes the Nebula glow.

Summary

As you can hopefully appreciate and see, the constellation of Orion is fascinating and well-worth some of your observing time, with binoculars or telescope.

It is known as “the Swan” because of its distinctive cross-shape in the sky. You can imagine it as a flying swan, with wings outstretched.

Cygnus has a declination of 29 degrees so it can be seen high in the sky to the south during the summer, from northerly latitudes. It is also visible to southern hemisphere observers.

Deneb

The brightest star, alpha-Cygni, is called Deneb (“the tail” from the Arabic).

Deneb is one of the brightest stars in our sky, having a magnitude of 1.2, in spite of it being 2000 light years away. Its absolute (or actual) magnitude is -7, which means it is 30,000 times brighter than our Sun.

Deneb is the most distant, first magnitude star.

Albireo

The double star Albireo (beta-Cygni), marks the head of the swan and it is a showpiece of the sky.

Look at it through a small telescope and you will see a pair of stars in contrasting colours. There is an amber star of magnitude 3, together with a blue-green star of magnitude 5. Beautiful!

The Milky Way

Cygnus lies in a particularly rich area of the sky for stars and clusters because we are looking here, into our own galaxy, the Milky Way.

On a dark and clear night, you can see with the unaided eye a “gap” in the Milky Way, to the side of Cygnus, called the “Cygnus Rift” or “Northern Coalsack”. It is not in fact a gap in the stars, but actually a dark area of dust produced by stellar explosions, that obscures our view of stars in this area.

Veil Nebula

Below the left arm (for northern observers) is an area of gas called the Veil Nebula. This is the remains of a supernova, or exploding star, from 30,000 years ago.

It is tricky to see without imaging the area, although you can see it under good conditions using a low-power telescope.

61-Cygni

This is a pair of orange dwarf stars, that are some of the closest stars to us (just 11 light years away). A good target for a small telescope.

The Coathanger

Below Albireo, towards the constellation of Aquila, is another good target for binoculars and small telescopes. It is not technically in Cygnus, but in the constellation of Vulpecula.

The Coathanger is a cluster of stars and the brightest ones, look just like an inverted coathanger.

Summary

For observers in the Northern hemisphere, the constellation of Cygnus make an interesting observation area. It is high in the sky, so you can see nice sights, even if the sky is not particularly dark.

However there is a problem…

As soon as you try observing the heavens with a handheld pair of binoculars, after just a few minutes, you will find out that it is not very comfortable.

Standing upright, trying to hold a pair of binoculars steady up to your eyes while gazing straight upwards, soon gets tiring and becomes a literal “pain in the neck”.

I have tried quite a few different ways for observing with binoculars in comfort, over the years.

Here are some ways you can try…

1. Use a deckchair or a reclining garden chair. This works pretty well. You can adjust the angle, depending on whether you want to observe up near the zenith, or at lower altitude in the sky. It is fairly comfortable, particularly if the garden chair has arms that you can position so you can rest your elbows and cut down the hand wobble.

2. Lay back, flat on the ground, preferably on a rug or groundsheet and maybe with a cushion under your head. Observing the stars through binoculars while in this position, can be amazing. If you let your imagination go, you can get a feeling of being “at one with the Universe”. But it does not give your arms or hands any support.

3. Get a tripod for your binoculars. This is perhaps the more dignified, grown-up approach. However not all binoculars and tripods will attach to each other. It tends to be only the large and specialist binoculars that come with a fixing point for a tripod. Also, and importantly, with a tripod you lose the easy mobility of a handheld pair of binoculars.

4. Make a special support frame to help your observing with binoculars in comfort. I have seen a simple wood frame made from 2″ square timber to provide support for the arms and binoculars. It has two legs, each with a “foot” and a crossbar. You lie on your back on the ground, with the frame over your chest. The crossbar should then be in the perfect position for resting your forearms and therefore, for supporting the weight of the binoculars. It might sound a bit weird, but with a couple of hours handy carpentry work, you could give it a try!

If you can come up with a comfortable arrangement for binocular observing, I am sure you will enjoy your astronomy much more.

But how do you go about choosing a suitable pair of binoculars for astronomy?

I would say that the key advantage of binoculars is their portability and ease of use. Consequently, you are going to want a reasonably lightweight and compact pair. This will rule out binoculars having particularly large lenses, but you will want to get a full-sized pair, rather than ultra-lightweight pocket versions, which usually have inferior image quality.

Let’s get specific and look at the numbers.

Binoculars are usually designated by a pair of numbers such as 8×40 or 10×50.

The first number in the pair is the magnification (or “power”), the second number is the diameter of each main lens in millimeters. So a pair of 8 x 40 binoculars will give a magnification of 8 times and each of the two main lens will be 40mm in diameter.

The bigger the lenses, the more light will be gathered, so enabling you to see fainter objects in the sky. But bigger lenses, mean heavier and larger binoculars.

You can get specialist binoculars having with lenses as large as 100mm, but these are like monsters! For general astronomy use, 50mm lenses are usually considered to be the best compromise.

With magnification, the higher the number the smaller the area of sky will be in the field of view.

You might think that a high magnification is good, but it means the binoculars become much more susceptable to movement in hands or arms, making the image shake. Also, the image degrades if magnification is too high for a given size of main lens. Consequently a magnification of 7 times or 10 times, is usually best.

So we come down to 7×50 or 10×50 binoculars, as being the best choice for general astronomy.

As regards price, you can get a very acceptable pair of binoculars for as little as $60 or £40. I have done this and have been pleased with the results. However you can of course, spend a lot more and get better quality.

The coating on the lenses is important. Higher quality lenses will have better “multicoated” lens. The coatings are intended to reduce internal reflection of light, within the binoculars as this degrades image quality.

Another factor to look for is field of view (FOV). More expensive binoculars may have “wide-angle” eyepieces. These give a wider field of view (for example, 8 degrees rather than 6 degrees), enabling you to see more sky at one time. This is good and makes it easier to see whole star constellations and so learn areas of the sky.

Another important advantage of wide-angle eyepieces is better “eye relief”. This means that your eye does not have to be as close to the eyepiece, to be able to see the full field of view. This is especially useful for spectacle wearers.

If you have the money, you can now get “image stabilized” binoculars. These have a built-in gyroscope mechanism that compensates for wobble and shake, by adjusting the internal optics in real time.

So you can enjoy a steady image, even if the binoculars are moving about somewhat. Image stabilized binoculars also allow higher magnifications, say 12 or 15 times to be used, while still being unmounted and handheld.

Excellent astronomy fun and discovery, can be had with nothing more than a pair of binoculars, plus a little knowledge and a good dollup of enthusiasm.

Binoculars have some great advantages over telescopes,  when it comes to astronomical observation:-

1. Binoculars are totally portable.
You can pick up even a large pair of binoculars, without thinking about it. You can take them easily to anywhere you plan to observe from, be it a friend’s house, your astronomy society meeting, a nearby dark location or even a star party.

2. Binoculars require no set-up.
A telescope it will need to be moved, together with its tripod and associated add-on equipment, to the observing position. It will usually then need to be positioned on a level surface and North aligned. If the telescope has a computerised drive, you will have to make sure the batteries are charged and then go through the initiation and set-up, followed by “training” the telescope drive so it can track and find stellar objects. This can easily take 15-45 minutes.

3. You keep both eyes open when observing.
For some people, this is a huge advantage. I have met many people who find it very difficult to close one eye, while looking with great detail and concentration through the other eye. Binoculars give a far more relaxed experience.

4. It is easy to find objects in the sky, through binoculars.
Yes, this is partly because the magnification is lower than with a telescope, but nevertheless, most find it fairly intuitive to point the binoculars on the small area of sky they want to observe and actually find it in the field of view.

5. Binoculars are not expensive.
My pair of 7×50 binoculars cost only about $60 and they work really well. You can get better quality, of course, but even for a high amateur standard, $200 or the equivalent should be more than adequate.

You should be able to observe many very interesting Night Sky objects with a reasonable pair of binoculars. To help you, I very much recommend my friend Robin Scagell’s book, Stargazing with Binoculars. (see image on the right).

The Moon is always good to look at. Also the star constellations.

The great thing about binocular observing is that you can get a whole constellation in the field of view, in one go. This encourages a nice familiarity with the shapes, which will help you find your way about the sky. Star clusters like the Pleiades are also excellent to view. Plus, many double stars can be easily “split” with decent binoculars.

I hope this article has given you the sense that binoculars can be really enjoyable for astronomy. They can open up the Night Sky easily, for a very small investment.