There are three main types of telescopes to choose from:
Each of these has it’s own advantages and disadvantages. I’ve explained the differences between these types of telescopes below. If there are any terms you are unfamiliar with, please refer to my glossary for an explanation.
A refracting telescope is the simplest type of telescope and probably the most recognizable. It’s design is so simple, that it is essentially a tube with a lens at each end.
How Refracting Telescopes Work
How refracting telescopes work, is actually very simple. Light enters through a main objective lens at one end (1).
The lens refracts, or bends, the light to a point of focus (2).
This is then magnified to form an image by the eyepiece at the other end (3).
Advantages of Refracting Telescopes
Because of their simple design, they are generally easy to use and more reliable as their optics are permanently fixed and aligned.
Disadvantages of Refracting Telescopes
They can be heavy, especially larger aperture telescopes, because of their need for large lenses. They can also have a longer body which may impact on transportation and storage. They may also be more expensive, as large high quality lenses are more costly to produce. Cheaper lenses are more susceptible to aberrations.
A reflecting telescope is similar to a refracting telescope, but just a little bit more complex. It is called a reflecting telescope because it uses mirrors to reflect the light internally.
How Reflecting Telescopes Work
As previously mentioned, the way a reflecting telescope works, is similar to reflectors.
This mirror reflects (3) the light into the eyepiece, which is usually mounted on the side of the telescope (4).
Advantages of Reflector Telescopes
Fairly compact and portable which is great for transportation and storage. Generally more affordable. Mirrors can produce less optical aberrations.
Disadvantages of Reflector Telescopes
Mirrors need regular re-alignment as they can easily slip out of alignment due to knocks and bumps or temperature changes. They can be susceptible to spherical aberrations.
The Catadioptric could be considered a hybrid refracting/reflecting telescope, in that it uses both mirrors and lenses to form the image.
How Catadioptric Telescopes Work
How a catadioptric telescope works is rather quite interesting.
Light enters at one end through a correcting lens, which helps reduce aberrations (1).
Advantages of Catadioptric Telescopes
Most catadioptrics are extremely compact and portable. The optics provide the advantages of both lenses and mirrors, so they make a great all purpose telescope.
Disadvantages of Catadioptric Telescopes
They may suffer a slight loss of light because of the positioning of the secondary mirror. Also catadioptrics may suffer from image shift, or a jump in focus, due to the primary mirror being moved when focusing.
Take The Next Step
If you are ready to begin star gazing, Amazon has a wide range of telescopes to suit all skill levels and budgets. You will find a selection of those currently available, listed below.