Newtonian telescope Details, Meaning Newtonian telescope Article and Explanation Guide

Newtonian telescope Guide, Meaning , Facts, Information and Description

The Newtonian telescope is a type of reflecting telescope invented by the British scientist Sir Isaac Newton (1643-1727), using a parabolic primary mirror and a flat diagonal secondary mirror.

Advantages of the Newtonian Design

Newtonians are usually less expensive than comparable telescopes of other types.
The primary mirror can be made by hand by amateur astronomers
A short focal_ratio can be obtained, leading to wide field, bright views.
Long focal_ratio Newtonian telescopes can give excellent planetary views.
There is no chromatic_abberation caused by lenses as in a refractor
The eyepiece is at the top end of the telescope, allowing for a shorter and more stable mount.
The heavy primary mirror is at the bottom allowing for large portable scopes. Dobsonian mounted Newtonians can have a 40" primary mirror.
Collimation is relatively easy.

Disadvantages of the Newtonian Design

Newtonians have coma, which is bluring of images away from the optical center. This problem is worse the shorter the focal length. Newtonians with a focal ratio of f/6 or higher are considered to have little to no coma. Newtonians of a focal ratio of less than f/4 are often considered to have too much coma.
Newtonians have a central obstruction due to the secondary mirror in the light path. This obstruction and the diffraction spikes caused by the support of the secondary mirror reduces contrast.

This is an Article on Newtonian telescope. Page Contains Information, Facts Details or Explanation Guide About Newtonian telescope

Newtonian telescope Guide, Meaning , Facts, Information and Description

Advantages of the Newtonian Design

Disadvantages of the Newtonian Design

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