Refracting vs Reflecting Telescope

best telescope

Which Is Better: A Refractor Telescope or a Reflector Telescope?

The answer to this question depends on what you are seeking from a telescope. So here’s a quick guide to help you decide the better telescope for your purpose. If you want to view:

  • The Moon: Refractor telescope
  • Planets: Reflector telescope
  • Deep space constellations, nebulas, star clusters: Reflector telescope
  • Beaches, Mountains, Landscapes: Refractor telescope
  • Buildings, Structures, People: Refractor telescope

Overall Selection Choice

From a general viewing perspective Refractor telescopes work well for viewing brighter objects like the moon and planets. Whereas Reflector telescopes are best suited for observing dimly lit deep-sky objects, like low magnitude stars, clusters, nebulas and the like.

With that said, let me know state that telescope technology, manufacturing processes and a myriad of other factors have resulted in a blurring of the distinction between the two different types of telescopes. So I think the better answer to the question of which telescope type is better, is that the buyer is better off considering:

  • The telescope construction and material quality
  • The sturdiness and stability of the tripod
  • The quality of the telescope mount and the ease of use
  • Other accessories (e.g., included lenses, accessory tray, finder scope, storage/carrying case)
  • Supporting features (e.g., computerized locator)
  • What budget is available
  • How does the buyer plan to use the telescope

Before I dive deeper into my answer and explain more, I wanted to share some information about each type of telescope.

Refractor Telescope

refractorThese optical varieties generally all use what is already in the visible portion of the electromagnetic spectrum, but they differ in how that light is focused (the type of objective) and presented to you. The refractor type uses a series of lenses to accomplish this. This objective lens is convex shaped and coordinated with an eyepiece so that whatever is being looked at will be amplified enough and gather more detail for you to see. These type of telescopes were very popular well into the late 19th century, and they may be good for historical purposes or if one is looking for a cheaper tool, then this might be a good option. However, the diameter of the lens (known as the aperture) is what determines much of a telescope’s power, and the next two types of telescopes allow for a larger one.

Reflector Telescope

reflector

The difference in a reflector version is that it uses mirrors in order to achieve the amplification that is done with a lens in the previous type. There might be multiple ones or just a single mirror, but in any case, these eponymous reflectors are curved in order to get a detailed image to your eye. One of the advantages of this type is that it does not produce the same chromatic aberrations that the refractors are known for, but there are still newly introduced focus issues depending on the total quality of the device.

Probably the greatest improvement of these over the older variety is that they allow for a much greater aperture so that these telescopes can be of a higher power in many cases. That is one of the reasons that they are practically ubiquitous when it comes to astronomy and the research within that field.

Technical Consideration Of The Objective Lens/Mirror

Taken from a technical and physical construction point of view, keep this one simple Rule-Of-Thumb in mind: The more light that a telescope is able to receive from an object being viewed, the better the viewing of the object will be for the observer.  Simply translated: “The larger the primary objective lens or mirror, the better the potential you have for seeing the object.”

Given the choice between a 3-inch Refractor and a 4-inch Reflector, I would pick the better light gathering capability of the 4-inch Reflector telescope.

reflector

Alternatively, if I have a choice between a 3-inch Reflector and a 4-inch Refractor, I would pick the better light gathering capability of the 4-inch Refractor telescope.

refractor

With this in mind, I try to avoid Refractor-Type telescopes if the primary objective lens is larger than 4 inches in diameter (approx 101 mm). This is because when the size of glass used for an objective lens exceeds 4-inches, the physical characteristics can be affected by temperature, humidity, and even the gravity. Specifically, the glass lens can expand, contract, and warp which will distort any image viewed through it. Additionally, the cost for producing a quality lens greater than 4 inches in diameter becomes increasingly more expensive because they require more advanced manufacturing techniques to help overcome some of the shortfalls.

Physical Construction Costs

When it comes to a physical construction cost comparison between a Refractor telescope and a Reflector telescope, there is one obvious fact: The construction of a Refractor telescope is relatively easier and simpler than a Reflector telescope.

A basic Refractor telescope consists of 1) a tubular body; 2) an objective lens, and 3) an eyepiece.

Compare this to a Reflector telescope which consists of 1) a tubular body; 2) an objective mirror; 3) a viewing mirror; 4) a viewing mirror holder, and 5) an eyepiece.

As a result, a person can research and find a Refractor telescope that is less expensive than a comparable Reflector telescope.

Terrestrial Viewing: Viewing Objects On Land

If one of your desires is to use the telescope for occasional viewing of land objects (e.g., buildings, mountains, beaches, boats, landscape), then I have found that a Refractor telescope works best for this purpose.

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