Wednesday, May 24, 2006

Reflecting telescope: Newtonian Telescope

Scientist Sir Isaac Newton (1643 - 1727) of Great Britain invented his own version of the telescope, which is a kind of reflecting telescope. This telescope of Newton utilizes two mirrors, one of which is parabolic in shape while the second is diagonal.

The parabolic mirror reflects an image to the diagonal second mirror. The image is then reflected by the diagonal mirror to an eyepiece which is mounted to the side near the top of the telescope tube. Newton’s use of the mirrors to focus light instead of lenses solved the problem of chromatic aberration. Chromatic aberration is the effect that occurs when light goes through a lens and colors were focused on different places, the result of which would be colors around the image.

The Newtonian telescope has one disadvantage – it suffers from instances of coma. Coma is an aberration that is off-axis in nature, meaning images flare away from the axis of the optics. Today, if your amateur telescope is Newtonian and you need to correct the coma – there are available lenses to bring back clarity and vividness of images. Check knowledgeable scope dealers in your area.

The Newtonian telescope is the simplest of all reflecting telescopes. Newtonians are indeed ideal as amateur telescope for stargazing newbies because it is relatively inexpensive, but still a very effective tool for astronomical endeavors.

The Newtonian is so simple that it is quite easy for amateurs to build a telescope of this type. Even the mirrors, especially the primary, can be built with quality by hobbyists.

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