If you ask someone to describe or draw a telescope, nine times out of ten it will be a refractor telescope.
The refractor telescope is quite possibly the most common or easily recognized telescope. It is a very simple design, which has been around for hundreds of years.
Refractors or refracting telescopes employ a simple optical system consisting of a hollow tube with a large primary or “objective lens” at one end, which refracts light collected by the objective lens and bends light rays to make them converge at a focal point.
Light waves which enter at an angle converge on the focal plane. It is the combination of both which form an image that is further refracted and magnified by a secondary lens which is actually the eyepiece. Different eyepieces give different magnifications.
The larger the size of the objective or primary lens = more light gathered. So a 6 inch refractor gathers more light than a 2 inch one. This means more detail can be seen.
Types of Refractor Telescopes
There are two main types of Refractor Telescopes: “Achromatic” – entry-level and upwards with 2 lens elements and “Apochromatic” – premium, advanced and expert level refractor telescopes with 3 or more very high quality lens elements with exotic mixes of materials.
Achromatic Refractor Telescopes are particularly good for observing bright objects such as the moon, planets and resolving things like double stars, but many astronomers who image deep sky and other objects use very high quality apochromatic refractors, due to their superior optics.
Qualities of Refractor Telescopes
Refractor Telescopes are very low maintenance due to being a sealed system and it is a simple case of setup and enjoy, without the fiddling lengthy setup times you may get with other telescopes.
Refractors give clean and crisp views due to the sealed nature, unlike other telescopes like Newtonians which are subject to cooling and air turbulence issues.
Due to their small size they are very portable and can also be used for terrestrial observations the same as binoculars, which are basically two refractors bolted together.
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