There is a massive range of telescopes to choose from which can be confusing if you are an amateur looking to buy your first telescope. One of the telescopes you might hear recommended for beginners is the Dobsonian telescope.
This type of telescope was developed by John Dobson back in the sixties as a way of making astronomy much cheaper and accessible to all. His invention led to the sidewalk astronomy event we still see today. The Dobsonian telescope is cheaper by virtue of its simple design. By removing the need for the large heavy and expensive mounts generally used by large reflector telescopes it became possible to put large aperture telescopes within the reach of amateurs.
The simplified design involves putting the scope tube on a simple turntable allowing it to swivel as well as hinge up and down, the same alt-az movement many simpler scopes use on tripods. By using this design it become possible for complete amateurs to use large aperture scopes to do deep sky viewing.
The advantage of large apertures is that high magnification can be achieved while keeping a sharp image for viewing.The general rule of thumb is to take the aperture in millimeters and multiply it by two to get the upper limit of magnification that can be gained with the right eyepieces.Thus a 12 inch dobsonian might achieve up to 600x magnification, whereas your little 3 inch refractor can achieve up to 150x.
Now while magnification is not actually the key to successful astronomy (it has its downsides too) the point made is that under good conditions, i.e. good dark skies, those big old 'Dobs' can allow for excellent deep sky viewing that can knock your socks off!
It is the ease of use, simple set-up and deep sky capabilities that makes these dobsonian telescopes so popular with amateurs and schools. If you have a good location to use one of these then these are an excellent purchase I can heartily recommend.
Want to find some bargain Dobsonian Telescopes? Check out the links below.
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