Typically, beginners will always think that the only kind of telescope is a telescope designed with lenses and eyepieces. However, this is only a refracting telescope, which was widely known thanks to Galileo’s inventions in the early 1600s.
In fact, there are reflecting telescopes based on mirrors, not just lenses. This type of telescope is designed with a mirror at the bottom of the tube and the eyepiece protrudes to the side. Isaac Newton invented this type of telescope in the mid-1600s, so it is often called the Newtonian reflecting telescope.
One question for new telescope users is the dissimilarity between refractor or a reflector telescope under $200 and which one is better. In this article, we will help you answer that question so that you make the best choice when buying a telescope.
What is A Refractor Telescope?
On the front of a refracting telescope, a curved lens is placed. When light passes through this lens, the light is bent and focused on a focal point in the optical tube. On the path of light, they place an eyepiece. People use a tripod to fix the telescope.
Nevertheless, you will have to kneel down to look through the eyepiece if the eyepiece is placed at the end of the tube and you point the telescope at the sky.
The light coming into the lens will go diagonally and will be bent at an angle of 90 degrees. This helps the position of the eyepiece to be adjusted so that the viewer will have a more convenient viewing position.
Typically, eyepieces are inserted diagonally. For daytime viewing, these refractor telescopes use diagonal lines at an angle of 45 degrees. However, when looking at the night sky, the diagonal line must be adjusted at an angle of 90 degrees.
Because the light is bent by the diagonal line, the image after going through the eyepiece will be reversed from left to right. However, in astronomy, the image is multidimensional, so this problem of left and right turn does not interfere with the observer.
When you want to see objects on the ground during the day through the refractor telescope, you can take a prism-shaped diagonal line to adjust this left / right flip.
All about Reflector Telescope (under $200)
This type of telescope is designed with an open-ended tube, a curved mirror, also known as the main mirror, placed at the bottom of the tube. This main mirror collects light and concentrates these rays into an auxiliary mirror that is partially placed on the tube.
To focus the light on the focus, the second mirror will be adjusted at an angle of 45 degrees. Unlike the above glass, this telescope doesn’t use diagonal lines to bend the light.
As illustrated, the Reflector Telescope is set up on a tripod. The mechanism of action is that light passes from the left to the mirror placed inside the right tube, after which the light is guided along a path to the eyepiece.
Therefore, this type of glass is only suitable for night vision because it provides reversible images. Due to the extended reflector design of the Reflector Telescope, the telescopes’ optical tubes are quite lengthy.
If a telescope has an 8 ”primary mirror adjusted at a focal ratio of 10 would call for a telescope tube which extends 80 inches. However, this long size will be quite inconvenient in practice, so people often adjust the focal ratio to F6 or lower.
In such a case, a tube that has 48 inches long will be suitable for an 8 ”F6 reflector.
Pros and cons of these two telescopes
The advantage of the Refracting Telescope is that at its center there are no obstructions. A mirror was designed to restrain some light from entering the tube to decrease the aperture.
Typically, telescopes will have five apertures, and the Refractor Telescope has the advantage of reducing the aperture to about 1 inch while retaining the ability to collect light, an important point in evaluating a telescope.
Moreover, thanks to the absence of secondary obstructions, Refractor Telescope will provide users with sharper images.
Chromatic aberration or CA is the most common disadvantage users encounter when using the Refracting Telescope. The light passing through the main lens will smash down its general color into multiple colors.
When the colors of the light do not reach the focus at the same time, there is a tendency to cause some color fringing on bright objects. However, this drawback has been overcome thanks to the use of two variations of refraction.
Newtonian Reflector Under $200
The price of a Newtonian reflector is the biggest advantage. The larger the size of a mirror, the cheaper it is to produce quality mirrors. For Newtonian Reflectors range from 2 “/ 50 mm to about 5” / 127 mm, the prices of those are quite similar.
However, when we get 5 ” or higher, the difference in cost becomes obvious. The difference of reflector telescope is that it can scale to 25 ”and larger. Although the price is cheap, the color quality of the image is still guaranteed.
The light is not separated into its color components, so users will not need to worry about chromatic aberrations. However, the disadvantage of the reflector telescope is the demand for regular collimation.
One difference of the Newtonian reflecting telescope is that the main mirror can be moved to align the optics thanks to the way they are mounted. Besides, for a large size Newtonian reflector, it will be easily modified by thermal expansion and contraction.
Which Would Be Better?
When choosing a telescope, you should consider the aperture. Large apertures allow you to adjust the magnification wider so you will see objects more clearly and more widely. Obviously, the larger the aperture is, the higher the price and the greater the weight.
If you are looking to own a telescope with an aperture of 4 or lower and pay attention to learning collimation then refraction is a telescope you are looking for. This type of telescope is also very solid and flexible.
You can easily take it with you when traveling or in your luggage when on board. In particular, to observe by refractor during the day, you just need to insert diagonal images exactly 45 degrees.
Conversely, if you want to see the night sky, you just need to switch to the 90-degree. Indeed, refraction is more versatile. On the other hand, if you want to buy a telescope with an aperture larger than 4 inches, you should buy a reflector telescope.
This type of telescope has a superior advantage in size and cost. When attaching a lens to a Dobsonian mount, this is a cost-effective solution that will keep your reflector telescope stable.
If you go to a Muslim star party where everyone carries a telescope, Newton/ Dobsonian designs are often the bigger ones.
In short, refractor or a reflector telescope under 200 all have their own advantages. Therefore, you should consider the cost and design factors to choose a suitable telescope.
What could be better than watching the vast universe with countless mysteries?