The Galileo refracting telescope, also known as refractors, are a preferred type of telescope among astronomy enthusiasts. It utilizes curved lenses to magnify faraway objects in deep space that cannot be seen with our eyes to give a larger and closer view. With a refracting telescope, you can view planetary bodies, the moon, nebulae, and galaxies. It is the most recommended type of scope for beginner astrographers.
The oldest refracting telescope is named after its inventor, the revered Italian scientist Galileo Galilei. Although not the first scientist to create the mechanism for refractors, Galileo upgraded in 1609. With this iteration, Galileo generated the first view of Jupiter’s largest satellites and discovered Venus’s phases, the geography of the moon, and the spots on the Sun.
While Galileo’s refracting telescope was way more rudimentary than the modern refracting telescope, his was the first practical refractor scope that yielded good enough images for deep space viewing and astronomy.
How do Refracting Telescopes work?
Refracting telescopes use two types of lenses to collect and focus light on distant objects. The lenses commonly used are the big objective lenses and the smaller eyepiece lenses, and they are shaped to bend light and magnify objects in view. The objective lens gathers light from an object and focuses on an image. The eyepiece lens placed at the back magnifies the image so that it is closer and larger when you look through the telescope.
The refracting telescope is a preferred scope type as they are compact and less hassling to use in the field. It is an excellent choice for astrophotographers. And astronomy enthusiasts as it yields great image quality and contrast compared to other scopes.
A refracting telescope. Copyright Jonathan Bell
Features of the Refracting Telescope
Powerful Optics
The design of refracting telescopes makes for better alignment of optics, and the aperture power allows more precise focus. This makes it very ideal for observing space objects. They have longer focal ratios that aid in viewing and capturing long-range objects. Refracting telescopes are known to yield superior image performance.
Portable and Suitable for Field Use
Refracting telescopes tend to be more compact and portable than their reflecting counterparts, making them easier to transport and set up. They also yield steadier images than most telescopes, which makes them better suited for field use. You can expect good images even in less-than-optimal conditions.
Minimal Maintenance
These telescopes are not high maintenance, making them a good choice for beginners. The viewing glass is protected from dust and other interruptive particles like air flow and temperatures. This allows the images yielded to be sharper and steadier than most other telescopes. Also, they are built steadily to prevent misalignment and give better ease of use.
No Light Path Interruption
As refracting telescopes use lenses, none of the interruptions on the light path are common with reflector telescopes (they use mirrors.) Refractors also have the edge over reflector telescopes as they bypass the diffraction spikes that usually occur with reflecting telescopes. This flaw somewhat removes the integrity of the images captured, but refractors are free of these errors.
Value for Money
Refractors may be a little higher than your budget, but for their prices, they are of high quality and have a longer focal length that gives a wonderful stargazing experience. There are refractors within reasonable price ranges, and are generally less expensive than other types of telescopes. This makes them ideal for those on a budget. Whether you are a beginner or an avid astronomer, refracting telescopes makes for an ideal choice of telescopes.
Refractors are preferred over reflectors of the same price range and quality. This is because the average refracting telescope yields steadier images in unfavorable conditions, allows more precise viewings, and has a good-quality field view.
Refractors are, however, not without certain drawbacks. Chromatic aberrations, such as color overlaps, occur when using a refracting telescope. If you are looking for the best choice of the telescope, you should consider more specific factors like the scope’s focal length, the aperture of the lenses, the quality of the field view, and how much of an error-free image it can yield.
Types of Refracting Telescopes
There are four major models of refracting telescopes, one of which is the Galileo refracting telescope mentioned at the start of this article.
The Galilean Telescope
The Galileo refracting telescope was the first functional telescope used for deep space observance. It consists of a convergent objective lens and a divergent eyepiece lens. This telescope has a less-than-optimal field view, and the lens shape yielded blurry images. However flawed in design, this was the most powerful refracting scope at the time.
The Keplerian Telescope
The eponymous telescope, named after its inventor, Johannes Kepler, was invented four years after Galileo’s. It improved the Galilean scope by using a convex eyepiece rather than the divergent lens used in Galileo’s. This meant that the field of view was broader and easier to view. However, the images this scope yields are inverted.
The Achromatic Telescope
Unlike the earlier versions of refracting telescopes, this scope yields images free of chromatic and spherical aberrations. The winning factor in this refractor type is the achromatic lenses used. These scopes also have shorter focal lengths, and while earlier iterations of this model had their drawbacks, such as smaller apertures, the achromatic telescope was the best of the 18th century. It was with this scope that Neptune and the Mars moon.
The Apochromatic Telescope
This telescope is an improvement on the achromatic telescope. It has the same features as the achromatic telescope but corrects the flaws with wavelengths and focuses on more color gametes. This means that the apochromatic telescope yields sharper and more color-accurate images with fewer chromatic aberrations. They are a perfect model of refractors for astrophotography.
For astronomy beginners looking to purchase a refractor scope with great specifications within a reasonable budget, these are the best options based on user reviews.
Founder Optics FOT106 triplet refractor
The FOT106 has an f/6 focal ratio, a focal length of 636mm, and objective lenses with an aperture of 106mm. This enables it to capture a larger view of galaxies, nebulae, and star clusters. It is beginner friendly and easy to mount and use.
Altair Starwave 70 EDQ-R Quad APO Imaging Refractor
This refractor telescope is great for beginners as it is lightweight, user-friendly, and suitable to use on the go. It has a focal length of 350mm and an f/5 focal length. This is an ideal scope choice if you are looking for a refractor with a broad field view.
Celestron StarSense Explorer DX 102
This scope is simple in design but great for locating deep-space objects as it has excellent optics and a large enough aperture. With an f/6.5 focal ratio, 660mm focal length, and magnifying eyepieces, the StarSense is a good choice of refractor telescope for beginners in astronomy.
