There are three main types of telescopes: reflector, refractor and catadioptric telescopes.
Reflectors have a main mirror to gather and focus light, whereas refractors have an objective lens. Catadioptrics have a main mirror, and a lens of the same diameter. All three of these types of telescopes have ‘sub-types’ which vary by design. For example, the most basic reflector telescopes have a Newtonian design, which means they have a main mirror and a smaller, secondary one to divert the light at right angles to the eyepiece from the top of the telescope.
As we’ve mentioned above, nowadays, you’re spoilt for choice when it comes to quality (and relatively affordable!) telescopes. So, which type should you opt for? We think Newtonian reflector telescopes on a simple undriven alt-azimuth mount (known as a ‘Dobsonian’) offer the best value in terms of aperture.
However, if you are interested in learning your way around the night sky ‘the old fashioned way’, then a Dobsonian telescope might be the way to go. They don’t come with any bells and whistles, so you’ll need to arm yourself with a star map to make sense of stargazing. Dobsonians collect a lot of light, and they have enough resolving power to deliver breathtaking views of celestial objects. Dobsonian telescopes over 6 inches in aperture tend to be pretty large and imposing, so you’ll need to consider where it can be stored if you purchase one. A garden shed or garage might be the best option.
If you add an equatorial or computerized mount, Newtonian or refractor telescopes become much more expensive. You can find several types of computerized mounts for Newtonian telescopes: Dobsonians (push-to or GoTo), single time-mounted (tracking or GoTo) and German equatorial (GoTo). For reference, for a computerized push-to Dobsonian, you’ll be looking at spending about twice as much than for a manual model of the same aperture, while a GoTo will set you back almost four times the price of its manual counterpart. A premium Newtonian on a German equatorial mount can be as much as ten times more expensive than one on a manual mount!
If ease of use, portability and convenience are high on your requirements, and you like gadgets, then a short focal length refractor of up to 4 inches or a catadioptric (Schmidt- or Maksutov-Cassegrain) up to 5 inches on a computerized mount may well fit the bill. These are versatile telescopes with high magnification which enables you to observe amazing details on the moon and planets.
Achromatic refractors with short focal lengths typically display a degree of false color around the edges of bright objects like the moon because they can’t focus all wavelengths of light to a precise point. Most users are happy to accept this drawback because refractors are so easy to use and care for; however, if you’re after a clean, high-contrast view without false color, the Maksutov is the best option here.
The best views of the night sky are obtained through apochromatic refractors. Using special glass objectives, they focus all wavelengths of light to as near a single point as possible and are free of false color. It is worth noting though that apochromats cost around four times as much as equivalent-sized achromats. It’s up to you whether you’re prepared to invest that kind of money into your skywatching.
