One of the first questions when considering a telescope is what is best: refractor vs reflector.
Although this is the most common debate, there are actually 3 main types of telescope:
- Refractor telescopes
- Reflector telescopes
- Catadioptric telescopes
Below we consider the pros and cons of each and recommend what telescope type is best for a beginner.
1. Refractor telescopes
Refractor telescopes (often also called just “refractors” or “refracting telescopes”) are the type that most people picture when they think of a telescope.
They feature the classic telescope tube that is narrower at one end where you look through and see what the other end is pointing at.
A refractor telescope uses a lens system to capture light. This is what distinguishes it from reflector telescopes that use mirror systems, and catadioptric telescopes that use a combination of mirrors and lenses.
For most people, especially beginners, the internal lens/mirrors system might seem unimportant but refractors, reflectors, and catadioptrics do have different characteristics that may make them more or less suitable for different telescope buyers.
Refractors were the first types of telescope invented in the 1600s. When amateur astronomy first became a popular hobby in the 1960s they were the best selling type of telescope. In the following decades, their popularity fell as other kinds of telescope emerged.
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However, in recent years refractor telescopes have become more popular again as technological advancements have improved their performance in relation to price.
In particular, the lenses have improved so the tubes can be shorter, and lighter materials have become more commonly used so they are less heavy.
Both these things together mean that the performance of refractors has improved in relation to size and weight, as well as cost.
The advantages of refractor telescopes are:
- They are the easiest to use of the three telescope types.
- They are usually portable and light to carry, so good as “grab-and-go” telescopes.
- They require the least maintenance of any of the three types of telescope. The lenses do not require any recoating as the mirrors occasionally do in reflector telescopes.
- No alignment or “collimation” of the telescope lens is needed.
- They generally provide good quality and performance in relation to price.
The disadvantages of refractor telescopes are:
- Some cheaper refractors can suffer from something called “chromatic aberration” which is distortion around the edge of the image. More advanced refractors do not suffer from this.
- They need time to adjust to the temperature if being taken from inside a warm house, to outside in the cold or else the image suffers.
- As you have to look in the end which is lower to the ground you may have to bend or stoop when viewing. This might not seem like a big issue, but it really is if you plan to spend a good deal of time in any one astronomy session.
Refractor telescope examples
Popular models of refractor telescopes include:
- Celestron 70mm Travel Scope
- Meade Instruments Infinity 60mm telescope
- Orion AstroView 90mm Equatorial Telescope
2. Reflector telescopes
Reflector telescopes are often just called “reflectors”, “reflective telescopes”, or “reflecting telescopes”.
In addition, they are also referred to as “Newtonian telescopes” as they were first constructed by Sir Isaac Newton in the 1600s (you can see his original telescope here).
You may also see them referred to as Dobsonian telescopes. This is specifically a Newtonian/reflector telescope on a specific type of mount (an altazimuth mount).
Reflector telescopes differ from refractors in that they use a system of mirrors, rather than a lens.
The light collected hits a mirror at the bottom of the telescope and then is reflected back up, and then out the side, into the eyepiece.
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Therefore, with a reflector, you look into an eyepiece that sits on the side of the telescope, rather than at the end.
Some people recommend large reflectors for beginners, however, we do not agree that this is the best choice.
The temptation to go for a reflector telescope is that you can get more bang for your buck, i.e. if you pay around the same price, you can get a more powerful reflector than you can refractor or compound telescope.
However, they are much harder to learn how to use in comparison to point-and-look refractors. In addition, they tend to be heavy and bulky.
The advantages of reflector telescopes are:
- They generally provide higher levels of performance in relation to price – that is, they offer the best aperture to price ratio.
- They can provide wide fields of view so you can see vast astronomy objects, like galaxies.
- They do not suffer from chromatic aberration (image distortion).
The disadvantages of reflector telescopes are:
- They can be big, heavy and hard to store.
- The eyepiece can be in an awkward position (particularly if used with on an equatorial mount).
- They can have issues to degrade performance as a result of the mirrors.
- They require collimation (a type of adjustment needed to ensure good imaging).
- They are generally the hardest to use for beginners.
Reflector telescope examples
Popular models of reflector telescopes include:
- Celestron PowerSeeker 127EQ telescope
- Orion SpaceProbe 130ST Equatorial telescope
- SkyWatcher Traditional Dobsonian 6-Inch
3. Catadioptric telescopes
Catadioptric telescopes (also known as compound telescopes) are the third type of telescope.
These use a mixture of the lens system of refractors, and the mirror system of reflectors.
The most common types of catadioptric telescopes are Schmidt-Cassegrains and Maksutov-Cassegrains. The differences relate to how they constructed internally.
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The advantages of catadioptric telescopes are:
- They are the most compact and lightweight telescope types, and so are easy to carry and assemble, as well as pack up and store.
- They have minimal viewing distortion.
- They are capable of good light gathering and wide field images.
- They have well-positioned eyepieces and are relatively easy to use.
The disadvantages of catadioptric telescopes are:
- They are generally the most expensive telescope type.
- They can suffer from light loss due to the multiple internal mirror systems.
- Like refractors, they require time to adjust to outdoor temperatures or what you can see if affected.
- They require adjusting each time (collimation).
Catadioptric telescope examples
Popular models of compound telescopes include:
- Celestron NexStar 127SLT Mak Computerized telescope
- Orion StarMax 127mm Equatorial Maksutov-Cassegrain telescope
- Meade Instruments 8-Inch Advanced Coma-Free telescope
What is best – refractor vs reflector vs catadioptric telescopes
In summary, the real takeaways you need about the 3 different telescope types are:
- Refractor telescopes are easiest to use but can be awkward for astronomy.
- Reflector telescopes provide good imaging and the best bang-for-buck in terms of power but are big, heavy and harder to use.
- Catadioptric telescopes are small and portable but are the most expensive
It’s worth really thinking about what is best for you when buying a telescope.
For most people, a catadioptric telescope would provide the right combination of power, ease of use, and practical size, but you’ll need a bigger budget to buy one.
If you don’t want to stretch that far, then you’ll want to work out where you want to compromise.
Broadly speaking, refractors in the same price bracket as reflectors will be less powerful (lower aperture) but will be easier to use and lighter and more practical.
See our guide here to the best telescopes to buy.
Over to you – Which is better a reflector or refractor telescope?
Let us know your thoughts on what you think is best here in the quiz or below in the comments.