In this era of technology, there are different telescopes that fulfill the desire to see the distant objects such as stars and galaxies. Among all, the Hubble space telescope is the prestigious telescopes. Hubble is launched in the outer orbit of Earth’s atmosphere which allows it to take extremely high-resolution images. Although the telescope is larger in size and heavy in weight, it travels with higher speed around the Earth at about 5 miles per second. In the frequency range of visible, infrared and ultraviolet light, astronomers can now have very clear views of the universe.
A few years back, it was very difficult to see the celestial bodies with the naked eye and their characteristic study was almost impossible. The invention of Ground-based telescopes made it easier for researchers to observe the celestial mechanics and the changes in the position of heavenly bodies. However, due to the low-resolution image, there were still certain challenges.
The need of the time was the invention of such kind of telescope which gave a clear image of faraway objects. The most difficult condition was to deal with the earth’s atmosphere as there are different radiations, as well as dust particles that distort the image process. Many space telescopes were launched in the space but the quality of the image remained the concerning part and also they were unable to work with the broad range of the electromagnetic spectrum.
Edwin Hubble made a versatile telescope with the collaboration of other astronomers. The Hubble Space Telescope launched in the lower orbit of the earth in 1990. Along with the dazzling array of pictures, Hubble collected large data in terabytes that provided an insight view of the universe . It is larger as compared to the size of the bus and equipped with different instruments that make it popular in image processing devices .
Hubble Space Telescope assembly
The light coming from the different objects is reflected from mirrors that are used inside the Hubble Space Telescope and the collimated beam of light is then analyzed by detectors.
Hubble space telescope has two mirrors that are based on an optical system so that it gives a unique view of the whole universe by gathering the light of different wavelengths. The main role in photography process is played by the mirrors as shown in Fig.1. Figure 1: Mirror’s arreangemet in the Hubble space telescope .
The primary ring has higher diameter as compared to the diameter of secondary ring. The detector is placed behind the primary mirror on which the image is formed. Mainly, the light travels through the telescope and hits the concave or primary mirror. The light is then reflected from the primary mirror to the front side of the telescope where it hits the secondary mirror or convex mirror.
The highly concentrated light in the shape of a beam, again travel towards the primary mirror and passes through the hole. Further processing is then done by other parts to analyze data.
The spectrograph works on the principle of spectroscopy that splits light into its components, similar to the prism. The characteristics of objects such as velocity, temperature, and chemical composition can be studied with the help of spectrography.
Two spectrographs are utilized in the Hubble namely, Space Telescope Origins Spectrograph (STIS) and the Cosmic Origins Spectrograph (COS). The detailed spectral data of celestial objects are provided by these two complementary instruments.
Hubble’s interferometers enable the telescope to focus on a steady aim. The three interferometers used in Hubble are known as Fine Guidance Sensors. While pointing towards a target, two among three of these sensors locked the telescope on target. The third sensor is then used to collect scientific information such as the position and the angular diameter of the target [3,4].
There are two primary cameras used in the Hubble Space Telescope that are known as Wide Field Camera 3 (WFC3) and the Advanced Camera for Surveys (ACS). These two cameras collectively provide the high resolution images of the cosmos over a wide range of wavelengths. The ACS can work in different wavelengths such as visible, infrared and ultraviolet light. The three secondary cameras are the part of ACS which perform their work in capturing different types of images. For the availability of more complex views, WFC3 performs its work as it expand the quality of image [4,5].
Characteristics of optical telescope
With the passage of time, different challenges were handled by making changes in the construction of the Hubble. According to the final design and performance.
Pros and cons of the Hubble Space Telescope
Before the invention of the Hubble space telescope, there were many unresolved mysteries about the universe. As the ground-based telescopes were capturing the faint images which were not enough to explain certain facts, became the main reason for the invention of spacecraft and now it is used in providing the detail of following phenomena:
Age of universe
As it was not possible before, to get knowledge about the age as well as the size of the universe, but due to the space telescope, astronomers got clues about the past appearance of galaxies .
Lifespan of planetary system
The study of stars was a challenge in ancient times. Now scientists have more detailed information about the composition and lifetime of the stars.
Existence of black hole
Until the arrival of the Hubble, observations regarding the black hole were impossible. The probability of the existence of a black hole and its gravitational effects can be observed now.
Unexpected phenomena in universe
The dramatic changes that happen suddenly in the planetary system can be detected quickly by the usage of spacecraft.
Detection of electromagnetic radiations
The biggest achievement of the scientists is dealing with the light of different wavelengths e.g. infrared, ultraviolet in image quality processing which will otherwise be absorbed or blocked by earth atmosphere while using a ground-based telescope [5,6].
Along with the remarkable advantages, the Hubble Space Telescope has certain limitations which are described below:
- Sun cannot be observed through the Hubble due to the high intensity of light however, its sensitive parts will be damaged. Similarly, those planets which are closer to the Sun namely, Venus and Mercury cannot be analyzed.
- Earth traps the solar particles with its magnetic effect and causes intense radiations in a particular region. The detectors cannot work properly in this zone and cause a delay in making observations .
- The detailed view of objects require more time of observation due to which the other objects cannot be analyzed in the meanwhile .
Hubble space telescope due to its unique features is the most efficient and reliable telescope for collecting information about the planetary system. As it is launched outside the Earth’s atmosphere, the high-resolution images are obtained. The Hubble space telescope is popular among astronomers while studying the detailed view of the universe. It’s working in infrared, visible and ultraviolet range is a remarkable achievement.
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