How does Telescope work?

How does Telescope work?

Astronomers use a tool to look at distant objects, which is known as Telescope. Telescopes work using curved mirrors to collect and focus light from the night sky. The first telescopes focused light using curved, transparent glass pieces, called lenses.

If the telescope collects 100 times more light than your eyes, then the image of a particular star in the telescope will look 100 times brighter. It lets you see many stars in a telescope that are too dim to see with the naked eye.

Today in this blog we will discuss how telescopes work and also about Hubble and James Webb Telescope.

How does Telescope work?

A telescope is a device that allows you to see distant objects very closely. It comes in all shapes and sizes. Telescopes are generally of two types, refractive and reflective. Refractive telescopes use lenses to focus light, while reflective telescopes use mirrors. To focus the light, a refractive telescope uses two lenses. It focuses on any object in such a way that the object is more to you than it really is. The shape of both lenses is called 'convex' which works by bending the light inwards, much like a diagram. This is the reason behind the small view of the image.

The world's largest refracting telescope is located at the University of Chicago's Yerkes Observatory in William Bay, Wisconsin, with an objective lens of 1.02 meters (40 inches) and a total power of 195x.

Now come to the reflecting telescope. This telescope does not use lenses at all. Instead of using lenses, they choose to use mirrors to focus light together. In this case, they use concave mirrors. Mirrors of this size also achieve the goal of bending light, except that they reflect light instead of bending it. There are even more telescopes that work by combining both lenses and mirrors.

How does the Hubble telescope work?

The Hubble Telescope is a space-based telescope, and space-based telescopes have some advantages over the Earth-based telescope. Pictures taken by the Hubble Space Telescope are truly amazing and beyond imagination in this world! NASA launched Hubble into low Earth orbit in 1990.

The Hubble telescope is a vivid example of a reflecting telescope that is capable of taking brighter and clearer images than any Earth-bound telescope from the depths of the Hubble universe away from the atmosphere. It collects light emitted from space objects with a 2.4-meter mirror and reflects the light towards its secondary mirror.

These mirrors focus light on scientific instruments such as cameras and spectrographs. These devices can detect and record three types of light in general: visible, ultraviolet, and infrared. The data collected by Hubble is sent to a tracking and data relay satellite, which sends it to a ground station.

And finally, the data goes to the space center from there.

How does the James Webb telescope work?

The James Webb Space Telescope is the world's largest, most powerful, and most complex space telescope ever built and launched into space. NASA and its partners want to share the experience of the first images of the Webb Space Telescope with the entire United States and overseas community. NASA and its partners invite community organizations to celebrate the first image from the James Webb Space Telescope.

The James Webb Space Telescope is designed to help us see the depths of the universe and understand the very beginnings of galaxies, stars, and planets. In order to see an object, the telescope must collect enough light from an object to produce an image.

There are two ways to increase the light-collecting capacity of a Hubble-like telescope - increase or decrease the size of the primary mirror as the telescope points toward an object. To "see" light from the oldest galaxies, which are about 13 billion light-years away, researchers have determined that JWST requires an initial mirror with a diameter of at least 6.5. The mirror must be light and small enough to fit into a meter space launch vehicle.

Another requirement is that JWST mirrors retain their shape at very cold temperatures up to 240°C since JWST will operate in deep space for approximately 5-10 years.

Significant differences between James Webb and Hubble

As we already know that Hubble was launched into low-Earth orbit in April 1990 whereas the James Web Telescope was launched in December 2021. Hubble Telescopes have helped us to get an idea of what the universe looks like by capturing beautiful images for more than three decades. The James Webb telescope, on the other hand, is designed to look at objects 10-100 times thinner than the Hubble.

The infrared portion of the JWST spectrum is designed to focus from 0.6 (red light) to 28 microns (infrared). This means that it will not be able to see in ultraviolet light like Hubble but will be able to focus on infrared bright objects like very distant galaxies.

The Hubble is like a large truck that is 13.2 m (43.5 ft.) Long and has a maximum diameter of 4.2 m (14 ft.). On the other side, about half of a large 737 aircraft is the JWST Sunshield which is 22 meters by 12 meters(69.5 ft x 46.5 ft).

According to Klaus Pontoppidan, Webb's photographs would be better than Hubble's and the images would be fundamentally 'different due to different wavelengths.

The Webb is primarily designed to detect infrared light, which leads to unique and stunning images whereas Hubble can observe light at optical and ultraviolet wavelengths.

Where the web telescope is about a million miles away, the Hubble is about 340 miles away. The Webb must be cooler than Hubble to capture the faint infrared wavelengths of light. The Webb, therefore, needs to be protected from the infrared radiation of the sun, earth, and moon.


we can say that a telescope has the effect of making your object many times larger than it is, even allowing you to see many thin objects in the dark. Telescopes work by collecting light from the sky, focusing on the barrel of an eyepiece, which enlarges and refines the focus of your eyes.

At 18th Apr 2023
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