Dobsonian Telescope

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February 19th, 2010 admin

Dobsonian Telescope

Choose a Good Beginners Telescope - Cut Through the Information Overload

So you've been bitten by the astronomy bug and want to get started with your very own telescope, but you're confused by the vast number of possible purchases? You are not alone, astronomy stores are accustomed to dealing with the confused beginner though of course not everybody has the opportunity to visit a specialist store. This article is intended to help cut through some of the confusion.

It's important to choose a telescope that is right for you, for example there is no point having a great big Dobsonian if you rarely get the chance to assemble it in a good dark sky location.

There are several factors to be considered from practical considerations like size, weight and portability to the price you can afford and indeed where you'll be doing the majority of your observing. Ignoring more advanced uses like astrophotography we might think along the following lines.

As a general rule, the larger the aperture the more you can expect out of your telescope. Refractors will generally outperform similar size reflectors. Refractors however are more expensive than reflectors, due to the extra high quality glass involved. They can also be impractical to handle at larger apertures where they can also reach very long tube lengths.

Large aperture reflectors can have comparatively short tubes and be very easy to handle as well as inexpensive. There is a little extra maintenance involved as you may need to clean and align the mirror from time to time, this procedure is known as collimation.

Catadioptric telescopes are a combination of refractor and reflector and are quite portable even at large apertures. A great many amateur astronomers who have access to good dark sky sites, ultimately end up with catadioptric telescopes because the offer a range of possibilities including astrophotography. The large ones, like most large aperture scopes, are not ideal in light polluted areas like the city and suburbs.

Those big Dobsonian telescopes are really just big reflectors mounted on simple turntables and their attraction is their huge light capture and simplicity of use, making them ideal for visual astronomy in a good location (again they are not so good in light polluted areas).

If you do not relish the thought of learning to find your way around the skies you could consider purchasing one of the models that come with a computerized mount. These 'Go-To' telescopes have made finding targets a breeze.

With those facts in mind you can now think about where you are going to do the most observing and choose a suitable beginners telescope. If you live in the city and are unlikely to get to a rural location for observing then perhaps stick with the small to medium size refractors, reflectors or catadioptrics, with or without the go-to function, your budget will probably start to dictate the choices here! If on the other hand you live in a dark sky area then my recommendation is to buy a great big Dobsonian. These offer so much viewing pleasure and are so simple to use it is difficult to fault them.

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See my Squidoo page for more on how to choose a good beginners telescope and some specific recommendations and absolute bargains!
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Telescopes for Beginners

i have an 8 inch dobsonian telescope, whats the best magnification i can get?

all i ver get is the outlines of the planets, and it shows up fairly small, what can i do to get really high magnification, what type of eyepieces do i neeed?

The planets *are* small dots in amateur telescopes.

With experience, you will learn to see the detail in those small dots.

The usual rule of thumb (2x per millimeter of aperture) says that the maximum magnification you would want to use on your telescope is 400x. This assumes perfect seeing, which rarely happens. Your views are usually limited by the atmosphere.