On a telescope, the most vital or most important part is the lens. The telescope has two positive or convex lenses, which are located close to the object called the objective lens, and which are located close to the eye (where the observer peers) are called the ocular lens. In the earth telescope, there is also a reversing lens, which functions to reverse the shadow without doing enlargement so that the final shadow formed can be upright as the direction of the original object. Once upon a time, a telescope was only a lens and frame and prioritized its function, but as time went on, the telescope was equipped with more complex parts.
Generally, telescopes are divided into three types, namely:
a. Reflector telescope
The reflector telescope is a telescope that uses a mirror as a substitute for the lens to capture light and reflect it.
b. Refractor telescope
Is a refractive telescope that consists of several glass lenses as a tool used to capture light and perform telescope functions.
c. Catadioptric telescope
A telescope that has a working system that is not much different from the two types of telescopes above. Because this telescope is an amalgamation of a refractor telescope and reflector, which uses two media to collect light, namely a mirror and a lens.
Examples of refractor telescopes are:
a. Earth Telescope
This telescope is also called the telescope in the field of the yojana telescope, which produces a final solid image of the direction of the original object. This is obtained from the results of using a third convex lens that places between the objective lens and the ocular lens near the eye. So that the third convex lens only has the function of reversing shadows without giving magnification, so this lens is also called a reversing lens.
b. Star Telescope
This telescope is also called an astronomical telescope used to observe outer space objects. Star telescopes use two positive lenses, each as an objective lens and eyepiece. Unlike the microscope, the telescope’s objective distance lens is greater than the focusing distance of the eyepiece.