In contrast to refracting telescopes, reflecting telescopes make use of the phenomena of reflection. Refracting telescopes employ lenses, while reflecting telescopes use mirrors.
An optical device known as a telescope collects light to create an image of an object in the distance. There are different sized telescopes available. For astronomical observation, very big telescopes are employed to peer into the deep sky. The amount of light entering the telescope is determined by its aperture. A telescope’s magnification is determined by the image’s aspect ratio in relation to the object’s size. While the lens performs this in refracting telescopes, curved mirrors like parabolic mirrors are employed in reflecting telescopes to focus a parallel beam of light on a target.
Both varieties of telescopes have benefits and drawbacks. Because they are simple to mount and repair, reflecting type telescopes are typically utilised on a big scale. Light is not absorbed or split in reflecting telescopes because light is reflected from the front side of the mirror.
Types of telescopes:
There are three primary telescopes Refractors, Newtonian reflectors, and catadioptric telescopes.
Newtonian Reflector Telescopes: Newtonian reflector telescopes typically employ a concave parabolic primary mirror to gather and focus incoming light onto a flat secondary mirror, which in turn reflects the image out of an opening at the side of the main tube and into the eyepiece.
Refractor Telescopes: The objective lens of a refractive telescope is located at the tube’s front. The light enters the eyepiece through the back of the tube. A right-angle diagonal is utilised to prevent neck strain because numerous observations are done high in the sky. Additionally, it offers an upright view, making them suited for observations on the ground. Compared to other designs, a refractor has a number of benefits. The tubes lack a central obstruction that would reduce the amount of light entering the tube, they have fixed optics that typically do not require collimation, and they are enclosed to prevent dust and moisture from entering the tube. Compared to other telescopes with a similar aperture, a refractor typically produces images of planets of higher quality.
Catadioptric telescopes are those that use a combination of mirrors and lenses to focus light. There are numerous variations of designs. The Schmidt-Cass grain and the Maksutov-Cassegrain are two examples of this. In a compound reflecting telescope, aberrations are often reduced using a full aperture lens. Since air currents are reduced, the corrector lens also improves the instrument’s performance. The main benefit of the design is that it yields a very portable telescope with a short physical length and a large focal length because the light path is folded back on itself.
The aperture of a telescope is significantly larger than the aperture of the human eye, making objects that are typically invisible to the unaided eye visible. The area of a telescope’s aperture determines how much light it can collect, so this factor depends on the mirror’s radius squared. As a result, a telescope with a 20 cm diameter gathers four times as many photons as one with a 10 cm diameter.