Overview:

A telescope is a tool that people use to see faraway places and objects and has played an important role in advancing our understanding of our planets and the cosmos. The first telescope was invented in 1608 by Hans Lippershey, a Dutch lensmaker, along with two other lensmakers, Zacharias Janssen and Jacob Metius, when they pear through the lenses they made and noticed how the object or place they were seeing was magnified 3 times. Galileo Galilei, an Italian astronomer and physicist, after hearing about the invention of Hans Lippershey, constructed and refined his version of the telescope, thus creating a telescope that could magnified 30 times (Library of Congress).

Early telescopes were very difficult to make. The problem is the challenge of shaping the concavity of the lenses needed for the telescope. Even in modern times, a good lens can cost $200 or more. Furthermore, the early model does not have a clear view when looking at the stars due to the color halo and the lack of filter protection against light radiation. Now in the present, many new models of the telescope, daily used by astronomers, continue to be developed and can cost around $300 to $8000, based on the OPT, the largest telescope retailer in the world (optcorp.com). 

Scientists who study astrology or people who are interested in seeing the stars, in general, will be interested in the telescope, for it was originally invented for the sole purpose of observing the stars. A telescope is meant to capture and magnify the light that is being transmitted by the star into our eyes, for us to see clearly what it looks like outside of our planet. Some powerful telescopes can capture an image of a star that’s a billion light years away and is extremely big. These types of telescopes are often used by astrologists. Without the telescope, scientists who study astrology would not be able to see and observe the world outside of our planet from the comfort of our homes. 

General Appearance: 

Telescopes used by astronomers are divided into 3 types, refractor, reflector, and catadioptric. The first telescope that Hans Lippershey made is considered a refractor, meaning a telescope that uses lenses to bend lights to focus. Then comes the reflector telescope which was first invented by Isaac Newton, which uses mirrors to bend light into focus, while catadioptric telescopes use both lenses and mirrors. Each telescope has its advantages and disadvantages which will be discussed later on. 

Refractor Telescopes:

A refractor telescope has a long tube, average size of 5 to 6 inches, attached to a Tripod Stand with the tube’s body diagonally facing toward the sky. The overall shape is somewhat like a cone being stretched with the bigger end facing toward the sky and the smaller end facing the ground. Most refracting telescopes consist of having two lenses, one lens at the front, which is the objective lens that focuses an image, and one at the back which is the eyepiece that makes the view come into view and magnified. The largest refractor telescope that was built so far was the “Great Refractor Telescope,” in Yerkes Observatory, which is 64-foot barrel long and weighs 6 tons. 

Reflector Telescopes:

The appearance of reflector telescopes have a more cylinder shape compared to refractor telescopes and the average size is commonly 6 to 8 inches. The telescope has a parabolic primary mirror at the back, from the opening of the telescope, that reflects the lights up towards the small hyperbolic secondary mirror located in the front. The hyperbolic secondary mirror will then bounds the light towards the eyepieces, and brings the light into focus. The small scope connecting to the reflector telescope is the finder scope.

Catadioptric Telescopes:

The appearance of a catadioptric telescope is similar to the reflector telescopes, in which the overall shape is cylindrical. However, the eyepieces for this telescope are located in the back like the refractor telescope. Besides the shape itself, the telescope also utilizes the advantage of both the refractor and reflector telescope by incorporating both the objective lens and the mirrors. 

Function/Purpose:

All three types of telescope share the same function of allowing people to observe the stars and places of great distance within the line of sight. You can adjust how far you can see through the focuser on the telescope, but there will be limits to the distance that you can see, depending on the telescope’s size and the type of telescope.

Components:

A telescope is divided into 6 major components: 

1. Mirror
2. Objective lenses
3. Optical tube
4. Eyepieces
5. Finderscope
6. Focusor
7. Mount
8. Tripod

How the telescope works is that first the mirror within the telescope is meant to reflect and store the light that is being emitted within the telescope, however, just that will not get you a clear view. Besides the mirror, you will need good objective lenses that will help focus the light toward the telescope. The theory is the same as how you start a fire by using a magnifying glass. Depending on the concavity of how the glass was shaped, it will change how the light is being focused. Next comes the eyepieces, this part of the telescope is at the small end of the telescope and is where you observe the distant view from the telescope. Besides that role, the eyepieces have another role of adjusting how far you can view into the distance. This is achieved through consisting of multiple numbers and types of lenses within it that help adjust/correct how light is being magnified before it reaches your eyes. It’s basically the same as what the objective lens does, but the difference is that you can move the lenses within the eyepiece through the focuser attached next to it. These three parts, the mirror, objective lenses, eyepieces, and focuser are virtually what allows the telescope to do what it does. In addition, the last two parts of a telescope are basically support items. The mount connects the telescope to the Tripod and is also what stabilizes the telescope from shaking, and the Tripod itself is the stand that lifts the telescope to where your head and eye level are.