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Shooting Stars
If you are a serious astronomy fanatic like a lot of us are, you can probably remember that one event in childhood that started you along this exciting hobby. It might have been that first time you looked through a telescope. But for many of us, it was that first time we saw a rain of fire from the sky that we eventually came to know as a meteoroid shower.
At the time when you see the first one, it�s easy to remember the movie �war of the worlds� or some other fantastic image of aliens entering our atmosphere in droves to take over the planet. But with some guidance and explanation of what was going on, we eventually learned that these showers were not at all threatening or any kind of invasion. For the most part meteoroid showers are harmless, part of nature and very fun to watch.
So what are these strange lights in the sky? Are they aliens invading from Mars? Are the comets coming to start the next ice age? Or perhaps asteroids burning up as they enter the earths atmosphere. The answer to the above questions is no to the first and �yes and no� to the other two.
A meteoroid is actually a small piece of space rubble, usually dust or small rocks that come from either a comet or the break up of an asteroid in space and that eventually plummets toward the earth. We say �toward the earth� because the lights you see are the friction of the atmosphere burning up those small space tidbits and creating a spectacular show for all of us as they do so. A particularly exciting moment to witness is when a meteoroid breaks up or explodes on entry. A meteoroid that explodes is called bolides.
There are some interesting details about the life of a meteoroid that make the viewing of shooting stars even more fun. To be seen, a meteoroid only needs to weigh as little as a millionth of a gram. But the thing that makes them so spectacular to see is the tremendous speeds they reach as they enter the atmosphere. Before burning up, a meteoroid will reach between 11 and 74 kilometers per second which is 100 times faster than a speeding bullet.
We tend to think of t seeing a shooting star as a freak event and we associate it with superstition (hence, wish on a lucky star). But there are actually thousands of them every year so it really isn�t that rare to see one. In fact, scientists tell us that over 200,000 tons of space matter enters the atmosphere each year and burns up on entry.
Comets are a big source of meteoroids because of the nature of those long tails. A large amount of dust, ice and other space debris gets caught up in a comet�s tail as it moves toward the sun. Then as the comet moves away from the sun in its orbit, tons of this matter is thrown off into space to disperse. As the Earth moves in its routine orbit around the sun, it often crosses through clouds of this discarded matter which becomes one of those �meteor showers� that are so popular for viewing.
These showers of shooting stars are pretty easy for astronomers to predict so you can get into position to see the excitement at just the right time of night and be looking at the right area of the night sky. Usually the astronomy magazine or site will give you a general time and location to be ready to look when the meteoroids start to fall.
Now keep in mind, this is a phenomenon of nature, so it may not observe the time table exactly. Also note that there is a notation system for where the meteoroid shower will occur based on what constellation is its backdrop. The section of the sky to focus on for the show is called the �radiant� because that is where the entering meteoroids begin to glow or radiate. The radiant is named for the constellation it is nearest too. So if the meteor shower is going to occur in the constellation of Leo, then its radiant will be called Leonid. This will help you decipher the listing of asteroid showers in the publications.
Space, The Final Frontier
While it was just a TV show, that little speech at the beginning of the original Star Trek show really did do a good job of capturing our feelings about space. It is those feelings that drive our love of astronomy and our desire to learn more and more about it.
The thing that is most exciting about studying the universe is also the most frustrating and that is that no matter how expert we get, we are always just getting started. But if it�s any consolation, some of the most advanced minds in science and from history always felt that way about space. Even the greats such as Copernicus and Einstein looked up into space and felt like they were just a spec in the presence of such infinity.
Of course space is not infinite. It has to be finite which means somehow there must be an end to it. But if there is, nobody on this tiny planet has figured out where it is. The only thing that has brought us to �the end of the universe� is our limited ability to see any deeper into space.
But conquering the final frontier of space means more than just seeing more stars and planets and building the biggest telescope we can. There are some mind blowing concepts about how space works that we have ahead of us to conquer. The big bang and the expanding universe alone was enough to set your mind to spinning. But then we have the coming of Einstein and the theory of relativity to set the entire idea on its ear. All of a sudden space is not just three dimensions but the dimension of time becomes exportable and the twisting and maybe even travel through time seems almost possible.
The frontier of space is as much a journey of the mind as it is of distance. When Steven Hawking showed us the mysteries of black holes, all of a sudden, time and space could collapse and be twisted and changed in those intergalactic pressure cookers. If not for the wonders of radio astronomy, these ideas would remain just ideas but slowly science is catching up with theory.
But the brilliance of mathematicians and genius minds like Hawking and Einstein continue to stretch our concepts of space. Now we have the string theory that could revolutionize everything we know about space, time and how the universe relates to itself. We can�t just say, no, we have discovered enough. It�s the final frontier. The Starship Enterprise would not stop exploring so neither can we. Because there is a hurdle still ahead that has a name but no real answer to it yet. It�s called the Unified Field Theory and those that know tell us that when the Einsteins and Hawkings of our day crack that theory, every other theory will fall into place.
These exciting concepts seem some tools to put the enormity of space in context. That may also be the value of science fiction. Not only are science fiction writers often the visionaries of what comes to be in the future but they give us the idea that space is knowable, that despite how big it is and how small we are, we can conquer this frontier like we have conquered others before us.
For mankind, that is often enough. If we can get the vision that we can conquer something, even if it is something so massive, so impossibly huge, it seems that we are capable of anything. And the love of astronomy, maybe unlike any other force on earth, has brought together mankind toward that common goal of conquering the universe. The quest to establish an international space station and to cooperate on spreading our reach off of this planet seems to find commonality between nations that otherwise cannot get along on the surface of the earth.
That alone may be a reason that we must continue to support astronomy locally and the space program nationally. It is something that seems to bring peace rather than war and make us a better people. But more than that it is as though this is what we were created to do. To reach out to the stars may be our destiny. If so then our love of astronomy is more than a hobby, it�s a calling.
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 Amazing Hubble
In the history of modern astronomy, there is probably no one greater leap forward than the building and launch of the space telescope known as the Hubble. While NASA has had many ups and downs, the launch and continued operation of the Hubble space telescope probably ranks next to the moon landings and the development of the Space Shuttle as one of the greatest space exploration accomplishments of the last hundred years.
An amazing piece of astronomy trivia that few people know is that in truth, only about ten percent of the universe is visible using conventional methods of observation. For that reason, the Hubble really was a huge leap forward. That is for the very simple reason that the Hubble can operate outside of the atmosphere of Earth. Trying to make significant space exploration via telescopes from the terrestrial surface of planet Earth is very difficult. That very thing that keeps us alive, our own Earth�s atmosphere presents a serious distraction from being able to see deeper and further into space.
The Hubble space telescope was named after the great scientist and visionary Edward Hubble who discovered that the universe was expanding which was explained by what is now known in science as Hubble�s Law. To truly get a feel for the amazing accomplishment that was achieved with the launch of the Hubble telescope, spend some time on Nasa�s web site dedicated to the project at http://hubble.nasa.gov. There are also a number of sites where you can enjoy some stunning pictures from the Hubble including http://heritage.stsci.edu/ and http://www.stsci.edu/ftp/science/hdf/hdf.html.
It�s hard to believe how long the Hubble has been orbiting earth and sending back amazing video and pictures of what it is discovering in space. But the Hubble was actually initially launched on April 25th 1990. It was the culmination of literally decades of research and construction which began in 1977. Expectations were high as the orbiting telescope was put in place and actually began to function as it was designed to do.
All was not always perfect with the telescope and the early pictures were disappointing. After some study NASA discovered that the reason for the early failures was the curvatures of one of the main lenses of the orbiting telescope.
We probably could never have kept this intricate piece of equipment operational as well as we have had we not had the Space Shuttle program to give us a tool to implement repairs and improvements to the Hubble. In 1993 a new lens was installed on the Hubble which corrected the problem of picture resolution that was noted in the early operation of the telescope.
Two other repair and upgrade mission have been made to the Hubble since it launched, both of them in 1997 to upgrade older equipment and to retrofit the telescope to extend its useful life through 2010. It�s pretty amazing to think that this scientific and mechanical marvel has been operating now for ten years without maintenance. We can be assured that plans are in the works for NASA to upgrade or replace parts on the Hubble to extend its useful life even further as that 2010 time frame draws closer.
It is hard to imagine the science of astronomy or the natural quest for greater knowledge of our universe without the Hubble. While many times those who would not fund space exploration have tried to cut funding for the Hubble, the operation of this telescope is just too important to astronomers and to the scientific well being of mankind and our planet not to continue to use the Hubble, or its next natural successor. We will always need to have a set of eyes in the sky to watch the universe and discover more of its mysteries.
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.
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.
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