mardi 18 août 2009

Astronomy

The History of Astronomy

If you have a passion for star gazing, telescopes, the Hubble and the universe and this thing we call “astronomy”, you are far from alone. Of course, we know that astronomy is a highly respected science that has produced some of the most amazing accomplishments of the twentieth century. On top of that, it is a thriving area of fascination and one of the most exciting hobby areas going with thousands of astronomy clubs and tens of thousands of amateur astronomers watching the stars every night just like we do.

But did you know that astronomy is one of the oldest and most respected sciences of them all? As far back as before the times of Christ, the wise and thinking people of societies of the time were looking at the stars and finding ways to track and chart them. We who love the hobby of astronomy can chart a proud history of astronomers that tracks across millennia and through virtually every culture in civilization. So for the sake of having some really good trivia to toss around at astronomy club next week, let’s highlight some of the big moments in the history of astronomy.

For many centuries the science of astronomy was not distinct from the practice of astrology. For clarity, astronomy is the study of the stars, planets, and the universe with a clearly scientific approach. Astrology is the study of the zodiac signs and how they influence our growth, our personalities and our daily lives. In modern times, we as people of science discount the astrological side and focus on the astronomy of the heavens. But they were one study for millennia before the age of science made them separate.

There is historical evidence that astronomy was a recognized science as far back as the Babylonian civilization hundreds of years before Christ. But the study of the stars was not limited to one country. There were similar movements going on in China, India, and Ancient Egypt and all over the Arabian Peninsula. The integration of astronomy and religion is so prevalent that we see it in the Christmas story in which the Magi, Zoroastrian priesthood probably from the equivalent of ancient Syria, followed a star to the Christ child. These astronomers were also astrologers and it was that mixture that lead them to be part of this historic event.

The first book on astronomy was written by Ptolemy during the Greek empire. Since that historic publication, the who’s who list of great astronomers charts a path right through the center of modern science including Copernicus, Galileo, Kepler, Sir Issac Newton, Jung, Michelangelo, Benjamin Franklin and more recently even Einstein and Stephen Hawkings would join that noble list. It seemed that from the renaissance on to this day, virtually any man or woman of intellect dabbled in astronomy at least somewhat and it has always been considered a sign of the learned to know about the universe and things astronomical.

Astronomy has had an impact on so many areas of our lives that we really don’t recognize. Many words in our language had their roots in astronomy such as…

* Influenza which comes from the Latin root word for influence. This reflects an early belief that the position of the moon and stars may influence health and cause or cure disease.

* Disaster which comes from the Latin for “bad star”.

* Lunatic which has the root word "Luna" in it which is the Latin word for moon. This highlights the long held belief that is even prevalent today that irrational behavior and even wild and dangerous things happen during a full moon.

Astronomy and its interrelationship with astrology has also influenced culture, education and religion to a very large extent over the centuries. In the English language, the first two days or our week, Sunday and Monday are a reference to astronomy as their literal interpretations would be “The Day of the Sun” and “The Day of the Moon.”

So if you have found astronomy becoming a consuming passion in your thoughts and what fascinates you about the world we live in, you are in great company as this area of study has been a major part of culture and thought virtually since the dawn of civilization. And it will continue to fascinate mankind for as long as those beautiful stars shine over our heads.







Astronomy Binoculars – A Great Alternative

It seems from the moment you begin to take your love of astronomy seriously, the thing that is on your mind is what kind of telescope will you get. And there is no question, investing in a good telescope can really enhance your enjoyment of your new passion in astronomy. But don’t be too hasty to keep up with the big wigs in the astronomy clubs that have advanced telescopes. There is another alternative that can give you most of the advantages of a telescope and some extra flexibility and reduced cost to boot.

That alternative is a good pair of astronomy binoculars. Mostly we think of binoculars as the thing you use to see the football game when you have to sit in the cheap seats. But if you do some homework and had a good grasp on what your stargazing objectives are, the advantages of astronomy binoculars over an entry level telescope can be pretty convincing.

* As a rule, they are cheaper. So you can get a lot of good stargazing at much less of an investment. You can always spend more money later but for now, this may be just the solution for you.

* There are not so many accessories. To own and operate a telescope takes a lot of orientation to how to set up and use the device. Beyond that, tuning it for optimum view and diagnosing it when you have problems can sometimes make the telescope more of the passion than stargazing itself.

* It is much easier to use. If you have not bought a telescope yet, you may have seen telescope owners going through a laborious set up and break down discipline for each use. This is time they are not looking at the stars. The binocular users are happily stargazing as this goes on.

* Binoculars are lightweight and portable. Unless you have the luxury to set up and operate an observatory from your deck, you are probably going to travel to perform your viewings. Binoculars go with you much easier and they are more lightweight to carry to the country and use while you are there than a cumbersome telescope set up kit.

So give the binocular option some consideration. To make the most effective choice, however, here are a few facts about astronomy binoculars that will help you evaluate which ones are best for you…

Binoculars have two lens sets, one at the end of the eyepiece and a set right next to your eyes. The ones closest to the eye are called the ocular lenses which magnify the image (make it bigger). The ones closest to the sky are called the objective lenses and the size of these lenses will determine how much sky you can see at once. So anytime you are evaluating binoculars, there are two numbers associated with the set. So if the binoculars have a rating of 15-40, that means that the ocular lenses magnify 15 times and the later number is a relative number to how much of the sky you can see. The higher the second number, the more you can see. The explanation is simple. The bigger the lens, the more light it lets in. But be aware that the bigger the second number, the larger, heavier and more cumbersome the binoculars will be.

You will have to balance these two numbers with both your budget and what you want the binoculars to do for you. If you decide to go with a lower power binoculars, you could become frustrated with what you can see and you may have to take your eyes away from the view to get your orientation and consult the star map more often because your range of vision is so limited.

There will also be a temptation to buy a set of binoculars that have zoom functions and other features that will allow you to use it for other purposes such as hunting, whale watching or seeing the football game from the cheap seats. While this is good economy, those functions will get in the way when you are using the binoculars for astronomy. So if you are considering this purchase as your alternative to buying a telescope, our advice is buy binoculars made just for astronomy and don’t take them to the ball game.







Astronomy or Astrology?

Have you ever finally just gave in to the temptation and read your horoscope in the newspaper on Sunday morning? Sure, we all have. For most of us, it’s a curiosity, an amusement to see what they say our day will be like based on the sign of the zodiac that we were born under. Sometimes we forget that this little diversion is actually part of an ancient science called astrology that has had a powerful effect on many cultures dating back to centuries before Christ.

That is not to say that astrology is a dead art today. It is easy to find astrology advocates in every town, advertising in the newspaper and on television trying to convince us that they can tell our fortune, our future and help cure our ills by exploring the mysteries of astrology.

When you are a lover of astronomy, the confusion between astronomy and astrology by those who don’t really understand the differences can get pretty aggravating. And in early civilizations, the two disciplines were not separate. Astrology was just the religious side of the science of astronomy. So what changed?

The most significant shift that set in motion the separation of the two lines of thought began in the first century when Ptolemy wrote the very first book on astronomy called the Tetrabiblos. In it, he began to suggest that astronomy should be considered a separate science from astrology. It was quite a revolutionary book because it also was the first scientific document to suggest that the earth was not the center of the universe and that astronomy should be focused strictly on the observation and recording of events in the cosmos.

Over the next 2000 years, we have come a long way. Not only has science and religion completely gone their separate ways since Ptolemy but the science of astronomy makes tremendous strides every year that are so phenomenal, Ptolemy would be truly astounded.

Probably the biggest point of diversion between a student of astrology and astronomy is the belief that the position of the stars has meaning over the events on our lives. Of course, we do know that the weather and tides and other important aspects of our lives are affected by the stars, planets and heavenly bodies, particularly the moon. But these things are happening because of completely explainable scientific laws in motion, not because of mystical forces at work.

What can we, as devotees of astronomy conclude about the close relationship between astrology and astronomy? Well, for sure we want to be able to explain to anyone who is confused by the similarity in the words what the differences are. We do not want to see the two approaches to the stars and planets to become confused again. But we should do all we can do keep that distinction clear without becoming skeptical or demeaning towards those who may still hold to the teachings of astrology.

It is important to remember that what is part of a person’s religious life has a level of sacred belief to the one holding it. And it is not respectful to scoff at such things. If for no other reason than out of respect for the ancient origins of astronomy, we should give courtesy who still are exploring whether astrology has any validity for them.

If we can treat each discipline with respect but maintain the separation that must exist between astrology and astronomy, there is no reason both approaches to our admiration of the galaxies cannot coexist in peace and harmony. And for our purposes as astronomers, that harmony will allow us plenty of freedom to enjoy our quest for knowledge for many more centuries to come. And who knows, you might still like to read the horoscope on Sunday morning every so often.







Radio Astronomy

For most of us, the idea of astronomy is something we directly connect to “stargazing”, telescopes and seeing magnificent displays in the heavens. And to be sure, that is the exciting area of astronomy that accounts for it’s huge popularity. So to the uninitiated, the idea of “radio astronomy” seems strange. There are two reasons for that. First is that humans are far more visual than audio oriented. And the second is that radio astronomy doesn’t really involve “listening” to the cosmos except to the extent that scientists who use this sophisticated form of “stargazing” do not rely on visual study to conduct their work.

To appreciate what is really exciting about radio astronomy, first we have to shift how we view astronomy. That is because to professional astronomers, studying the universe is more about frequencies than it is about visual documentation of phenomenon. This takes us back to Physics 101.

Light, obviously, is the physical phenomenon that empowers our ability to use our visual confirmation system, e.g. our eyes to appreciate something, in this case the stars. So when we look up at the heavens, we can see the light emitting from a star or reflecting from a planet or moon. In many cases, if we see a far away star, we are actually seeing it hundreds or thousands of years ago because that is how long it takes for that light to cross the universe and be visible in our sky. That alone is a pretty mind blowing idea.

Now light itself is a pretty strange substance. But to our astronomy scientists, light is just another energy that exists in a certain frequency. Now, we tend to think of frequencies when we talk about sound waves. In scientific terms light, energy and sound are just a few forms of the same thing, frequencies of energy that are emulating from a source.

Now we get to why radio astronomy is so necessary. The range of frequency that light occupies in the big spectrum of frequencies is really pretty small. To put that more bluntly, we can only “see” a tiny part of the universe that is actually there. Now when you look up in the night sky and it is so overwhelming, when you then that we are seeing just a tiny amount of what is actually going on up there, again, our minds can get pretty overwhelmed.

Radio astronomy uses sophisticated sensor equipment to study ALL of the frequencies of energy coming to us from the cosmos. In that way, these scientists can “see” everything that is going on out there and so get a precise idea of how the stars look, behave now and will behave in the future.

For some of us who have heard about radio astronomy, we think of it in terms of “listening” for signs of life in the universe. And yes, SETI, or “the Search for Extra Terrestrial Intelligence” is a part of radio astronomy, albeit a tiny part. But of much greater importance is how radio astronomy has empowered serious astronomers (that is those who get paid to do it) to study stars many light years away, to study black holes which we could never see with our telescopes and to gather research and data about the whole of the universe that otherwise would be impossible to know and understand.

This is important work that is constantly ongoing in the world of astronomy. It is worth keeping up with and learning more about as we have barely scratched the surface in our brief discussion today. But understanding how important radio astronomy is will only deepen and make more meaningful your love and grasp of this big field of knowledge known as astronomy.



Telescopes

Telescopes 101

Buying the right telescope to take your love of astronomy to the next level is a big next step in the development of your passion for the stars. In many ways, it is a big step from someone who is just fooling around with astronomy to a serious student of the science. But you and I both know that there is still another big step after buying a telescope before you really know how to use it.

So it is critically important that you get just the right telescope for where you are and what your star gazing preferences are. To start with, let’s discuss the three major kinds of telescopes and then lay down some “Telescope 101” concepts to increase your chances that you will buy the right thing.

The three primary types of telescopes that the amateur astronomer might buy are the Refractor, the Reflector and the Schmidt Cassegrain telescope. The first two are named for the kind of lens that is used. It is pretty easy to see that the lens is the heart of the telescope so the kind that you will use will determine the success of your use of that telescope.

The refractor lens is the simplest because it uses a convex lens to focus the light on the eyepiece. So the lens bends outwards for this purpose. The refractor telescope’s strength is in viewing planets. The reflector’s strength is in seeing more distant objects and the lens is concave or bends in. It uses mirrors to focus the image that you eventually see. The final type, the Schmidt Cassegrain telescope is the most complex and accomplishes the goals of both but it uses an involved system of mirrors to capture the image you want to see.

So to select just the right kind of telescope, your objectives in using the telescope are important. To really understand the strengths and weaknesses not only of the lenses and telescope design but also in how the telescope performs in various star gazing situations, it is best to do some homework up front and get exposure to the different kinds. So before you make your first purchase…

* Above all, establish a relationship with a reputable telescope shop that employs people who know their stuff. If you buy your telescope at a Wal-Mart or department store, the odds you will get the right thing are remote.

* Pick the brains of the experts. If you are not already active in an astronomy society or club, the sales people at the telescope store will be able to guide you to the active societies in your area. Once you have connections with people who have bought telescopes, you can get advice about what works and what to avoid that is more valid than anything you will get from a web article or a salesperson at Wal-Mart.

* Try before you buy. This is another advantage of going on some field trips with the astronomy club. You can set aside some quality hours with people who know telescopes and have their rigs set up to examine their equipment, learn the key technical aspects, and try them out before you sink money in your own set up.

There are other considerations to factor into your final purchase decision. How mobile must your telescope be? The tripod or other accessory decisions will change significantly with a telescope that will live on your deck versus one that you plan to take to many remote locations. Along those lines, how difficult is the set up and break down? How complex is the telescope and will you have trouble with maintenance? Network to get the answers to these and other questions. If you do your homework like this, you will find just the right telescope for this next big step in the evolution of your passion for astronomy.







The Glossary of Telescopes

When you enter into any new area of science, you almost always find yourself with a baffling new language of technical terms to learn before you can converse with the experts. This is certainly true in astronomy both in terms of terms that refer to the cosmos and terms that describe the tools of the trade, the most prevalent being the telescope. So to get us off of first base, let’s define some of the key terms that pertain to telescopes to help you be able to talk to them more intelligently.

The first area of specialization in telescopes has to do with the types of telescopes people use. The three designs of telescopes that most people use are the Refractor, the Reflector and the Schmidt Cassegrain telescope.

* The refractor telescope uses a convex lens to focus the light on the eyepiece.

* The reflector telescope has a concave lens which means it bends in. It uses mirrors to focus the image that you eventually see.

* The Schmidt Cassegrain telescope uses an involved system of mirrors to capture the image you want to see.

* A binocular telescope uses a set of telescopes mounted and synchronized so your view of the sky is 3-D.

Beyond the basic types, other terms refer to parts of the telescope or to the science behind how telescopes work.

* Collimation is a term for how well tuned the telescope is to give you a good clear image of what you are looking at. You want your telescope to have good collimation so you are not getting a false image of the celestial body.

* Aperture is a fancy word for how big the lens of your telescope is. But it’s an important word because the aperture of the lens is the key to how powerful your telescope is. Magnification has nothing to do with it, its all in the aperture.

* Focuser is the housing that keeps the eyepiece of the telescope, or what you will look through, in place. The focuser has to be stable and in good repair for you to have an image you can rely on.

* Mount and Wedge. Both of these terms refer to the tripod your telescope sits on. The mount is the actual tripod and the wedge is the device that lets you attach the telescope to the mount. The mount and the wedge are there to assist you with a superior viewing session and to keep your expensive telescope safe from a fall.

* An Altazimuth Mount refers to the tripod of the telescope that holds the device in place and makes it useful during a star gazing session. The altazimuth mouth allows the telescope to move both horizontally (which is the azimuth) and vertically. In this way you have full range to look at things close to the horizon or directly overhead.

* Coma has a different meaning than the one we are used to, and that’s a good thing. The coma is the blurry area on the outer rims of your view through the telescope. How big the coma is and to what extent it interferes with your viewing will have is important to the effectiveness of your telesscope.

* Planisphere. A fancy word for a star chart. It is nothing less or more than a detailed map of where everything is in the cosmos and how to find the star you wish to study by keying off of known stars.

* Barlow. This refers to a specialized type of lens that you can buy to enhance the magnification of your telescope.

These are just a few of the basic concepts of telescope operation. We deliberately picked the ones you have to know to discuss telescopes intelligently. But your education into the more complex aspects of astronomy and telescope design and operation will go on for as long as you are a lover of astronomy, which we hope is for the rest of your life.







The Basics of Buying a Telescope

There is a moment in the life of any aspiring astronomer that it is time to buy that first telescope. It’s exciting to think about setting up your own viewing station whether that is on the deck of your home or having a powerful but mobile telescope set up to take to the remove countryside to really get a good shot at some breath taking star gazing.

The last thing we would want to do is to take away any of the “fun” of your hobby of astronomy because the joy of what we do as star gazers is a big part of the appeal. But unlike many other hobbies, ours is a passion of science, of learning and of discovery. And don’t kid yourself, even a hobbyist with a limited telescopic set up can see some amazing things in the stars. So let’s be sure you invest in a solid piece of equipment that you can continue to grow with as your knowledge and ability as an astronomer grows. But how do we do that?

Meet the Geeks.
Now we use the term “telescope geeks” lovingly because any of us who are devoted to our love of astronomy eventually become telescope geeks. And these are the type of people who will know exactly how to evaluate your needs in terms of where you are right now and where you want to go as your hobby grows with you. So if you have not yet associated with a local astronomy club, now is the time to do it.

Start rubbing elbows with people who live and breathe telescopes. Their input is a hundred times more reliable than what a sales brochure or that salesman might have to say because the “telescope geeks” have been where you are, made the mistakes and are eager to help you avoid those same mistakes.

Size Matters
In the world of telescopes, the sales people see, to try to baffle us with all the bells and whistles of their hottest selling model. One of the big check points that is often pushed is the amplification level of the telescope lens. While that is a factor that is worth noting, when it comes to a telescope lens, the old phrase “size matters” is a good guideline.

Just remember that your telescope lens works best when it takes in the most light it can from the object you are viewing. So the wider the diameter of the lens, the better a view you are going to get. So don’t fall for the amplification level only. Carefully evaluate the lens size so you have the right fit for what you want to do.

It Has to Stand on Its Own Feet.
If you are going to set up a permanent telescope station, then you can bolt the unit down so it is well supported. But many of us have to take our telescopes out into the country for optimum use. So the stand has to be strong and flexible so we can set up the telescope on uneven turf but still feel secure that this important and expensive piece of equipment is going to stand on its own without fear of it falling during our observation time.

We already mentioned strong and flexible as evaluation guides for the telescope stand but add in ease of use as well. You have to be able to set your telescope up and break it down quickly and easily when you are on a remote viewing. You may even find yourself setting up or taking down your telescope in the dark or by lantern or flashlight if you are taking advantage of the great star displays in the late night sky that make this hobby so exciting.

These are the basics of what to look for in your new telescope. Finally, make sure the telescope can be enhanced and expanded without having to throw the first unit away and buy something completely new. You want your telescope to grow as your knowledge and skills grow. If your first telescope meets all of these requirements, you are off on the right foot on a long and enjoyable career as an amateur astronomer.






Dude, You’re Getting a Telescope!

You might remember the Dell computer commercials in which a youth reports this exciting news to his friends that they are about to get their new computer by telling them, “Dude, you’re getting a Dell!” It was a cute series but it reflects the excitement young people get about anything new, particularly if it’s a new machine.

So when its time to finally get your children that very first telescope, you want to make sure it’s just the right thing. There are a number of reasons you should put some serious thought into just what this beginner telescope should look like. Perhaps this will be your children’s first experience with a real telescope. They may have a healthy and thriving love of astronomy from your family trips to the country to watch a meteor shower or just to gaze at the stars. And you may have piqued their interest showing them how to enhance the experience with binoculars or even letting them play with your telescope.

But this is a big moment. You want them to “bond” with this first telescope the way you did and catch the excitement of using the power of a telescope to do things with their love of astronomy that they could never do before. The reasons for taking care with your choice are many including…

* A telescope is a big step into the lifelong hobby of astronomy. If they get the wrong thing, frustration could make them lose interest both in the machine and in the field of study.
* Kids have a short attention span. You want this beginner telescope to take them from where they are to the next level while giving them those gratifying moments discovering new things in the stars every time they use it.
* It has to be a hardy piece of equipment. Kids don’t always know how to treat delicate equipment. So the starter telescope should have some good “training wheels” on it.
* It has to be their teacher even when they don’t know they are in school. A good beginner telescope, accompanied by some stimulating documentation that is written just for kids will stimulate their excitement and use it to teach them to work hard to reach new heights in their quest for knowledge about the stars.

A lot about how you go about getting this first telescope will depend on your own expertise in astronomy. If it is your passion and you have developed a pretty sophisticated knowledge about telescopes over the years, you not only are well equipped to make this choice but you will be there to guide them as they begin to use it.

But if you are just encouraging them in a wonderful hobby that you yourself have not been involved with in depth, first of all, congratulations. You are giving them a wonderful gift of not only knowledge but the love of astronomy and the natural wonder of nature. But you also need some help. So here are some quick guidelines.

* Find the astronomy geeks. They are easy to find in hobby shops, astronomy clubs and societies at the local college. They will help you enthusiastically.
* Look at the telescope you are considering through their eyes. It should not be too complex. Don’t get something that will intimidate them.
* Don’t buy a toy. Your kids will know the difference.
* Make sure it can grow and be expanded as their knowledge expands.

If you put some wise consideration into just the right starter telescope, your kids will be as excited they have ever been for a gift. Don’t be surprised if you hear one of them squeal, “Dude, you got a telescope!”