Telescopes 101

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.

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