Friday 14 April 2017

The Basics of Buying a Telescope

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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