Three basic components of a modern astronomical instrument are Telescope, detectors, and a sorting instrument. A telescope is primarily used to collect and measure light or radiation coming emitted by an object. It is capable of containing more amount of light compared to human eyes. For the detectors, they recognize the areas of the selected wavelength radiation and permanently records the observation. Thirdly, a sorting instrument is usually connected to the Telescope, and functions to categorize the visible light based on wavelength.
Two spectral windows through which electromagnetic radiation reaches the surface of the Earth are Radio Waves and Visible Wavebands. The largest-aperture Telescope currently in use for each window is the Gran Telescope Canarias, with a 305-m primary mirror. The largest single-dish radio telescope in Arecibo telescope.
Largest-aperture single Telescope currently in use in each of the following brands of the electromagnetic spectrum: radio -305- m primary mirror, X-ray – Chandra in space, gamma-ray – FERMI, in space.
Astronomers discuss the apertures of their telescopes by saying bigger is better. When the aperture is more prominent, it creates room for more magnification, thus producing higher resolution. Besides, it can detect fainter sources instead of smaller ones since it collects light making for a sharper image.
The Hooker telescope at Palomar Observatory has a 5 m, and the Keck I telescope has a diameter of 10 m. Keck telescope can collect four times as much asHooker Telescope in the same amount of time.
Reflecting Telescope uses the mirror to form images instead of a lens. At the same time, Refracting Telescope utilizes the lens as the central optical element for image formation because it has a long tube containing a large glass lens at one end.
The largest visible-light telescopes in the world are made with mirrors rather than lenses because they use a small secondary mirror that permits more light to go through the system, hence getting more clear images.
Compare the eye, photographic film, and CCDs as detectors for light. What are the advantages and disadvantages of each? The eye is cheaper and comfortable, and at the same time, an eye is not perfect since humans usually process with their imperfect brains. Also, it has a limited integration time. The photographic film uses a photographic plate that creates an irreversible record. The photographic film tends to be expensive and inefficient. It’s only a mere 1% of the light that leads to the chemical change for image formation. CCDs can collect light over a long period similar to a phone camera hoked to a telescope.
A charge-coupled device (CCD) is a light-sensitive integrated circuit storing and displaying information for an image. A single picture element in an image is changed into an electrical charge. It is used in astronomy to detecting light.
Why is it difficult at infrared wavelengths? Because distinguishing the amount of heat radiation reaching the Earth’s surface from the stars and galaxies and that radiated by Telescope is somewhat difficult. What do astronomers do to address this difficulty? It is a prerequisite for astronomers to protect the infrared detector, usually by cooling. They can as well keep the sensor in space or mountains.
Radio and radar observations are often made with the same antenna, but they are very different techniques. Compare and contrast radio and radar astronomy in terms of the equipment needed, the methods used, and the kind of results obtained—a radio consists of a dish reflector, spectrometer, and a detector. The dish functions as a mirror as it reflects Telescope, collecting and focusing radiation. It capable of detecting objects that are far away. In radar, a radio dish functions as a radar telescope on instances fitted with superior transmitters and receivers. A radar emitter is necessary for the experiment, and it is only capable of detecting closer objects.
Look back at Figure 6.18 of Cygnus A and read its caption again. The material in the giant lobes at the edges of the image had to have been ejected from the center at least how many years ago? 160, 000 years ago
Astronomers place telescopes in Earth’s orbit to get above the atmosphere’s distorting effects to a visible and infrared wavelengths. The advantages for the different spectrum regions include bypassing Earth’s limiters such as clouds, storms, and moisture. It eliminates Earth’s distractors.
What was the problem with the Hubble Space Telescope, and how was it solved? Following the Hubble Space Telescope launching, there was some detectable error in the shape of the primary mirror. To resolve the situation, scientists fixed a collector plate serving to boost the camera prior to releasing HTS back into the orbit.
Describe the techniques radio astronomers use to obtain a resolution comparable to what astronomers working with visible light can achieve. It uses an interferometer as an image sharpener as it links several telescopes together electronically. Astronomers integrate a significant figure of radio dishes into an interferometer.
What kind of visible-light and infrared telescopes on the ground are astronomers planning for the future? Why are they building them on the ground and not in space?
In 2021, astronomers are planning to make a massive 8.4 – meter Large Synoptic Survey Telescope. Building such a telescope in space will be very expensive and at the same time is heavy.
Describe one visible-light or infrared Telescope that astronomers are planning to launch into space in the future. Scientists anticipate making James Webb Space Telescope (JWST), and to prevents the Earth’s substantial infrared glow interference, it will be launched into a solar orbit.