The word “telescope” tends to conjure images of long, thin tubes most associated with stargazing by the amateur astronomer, but there are in fact many different types of telescopes. Things as simple as binoculars are in the same family as telescopes, as well as complex, sophisticated pieces of machinery, such as the famous Hubble Telescope. One type of telescope is the Newtonian telescope, which indeed has a long tube, but the width is often closer to that of a can of paint than anything skinny. Rather than look at one end of the tube, the design of the Newtonian telescope lends itself more to looking through an eyepiece in the side of the tube. The simple design and power of the Newtonian telescope makes it a great idea for the hobbyist astronomer.
Newton’s Invention
As the name implies, Sir Isaac Newton invented this particular telescope in order to study the skies, so this telescope’s design is one that has held up for hundreds of years. The main difference between a Newtonian telescope and a traditional telescope is that rather than using multiple lenses to focus light for viewing, a concave mirror at one end of the telescope concentrates and focuses the light to another mirror and viewed through the eyepiece. This sort of construction is quite simple, similar to the design of a periscope in how the reflections are handled.
There are some advantages and disadvantages to such a design. Newtonian telescopes tend to give great views of planets, and their design naturally lends itself to allowing a wider field of view than the generic telescope. Because the design is not based of using precisely ground lenses, the cost of a Newtonian telescope is much less than that of a traditional telescope and the light is not distorted at certain wavelengths, as it would be if passed through a lens. On the other hand, the curved mirror does create some distortion of the images seen, and the two mirror design does mean that the mirror used to reflect the light to the eyepiece is right in the middle of the main path of light, creating an obstruction right in the middle of the image.
Make Your Own Telescope!
One of the coolest things about the design of the Newtonian telescope is that amateur hobbyists can build their own. Of course, the mirrors have to be purchased, but the main tube can be created from a wide length of PVC pipe. With just a handful of materials, a home astronomer can create their own telescope, and the best part of that is this does not necessarily sacrifice quality, since the Newtonian telescope is an established, quality invention. But even if you chose to purchase rather than construct your own telescope, the Newtonian telescope often offers more viewing power for the price. Newton’s simple invention has stood the test of time and even after hundreds of years of technological development, this telescope is still a solid item to have for an avid sky gazer.
