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OTHER TELESCOPES. OTHER TELESCOPES. Radio telescopes Fundamental design similar to optical telescopes. Made up of large dishes to accommodate longer wavelengths of electromagnetic radiation. Bowl-shaped surface is crafted of steel and wire mesh. . Radio Telescopes.
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OTHER TELESCOPES • Radio telescopes • Fundamental design similar to optical telescopes. • Made up of large dishes to accommodate longer wavelengths of electromagnetic radiation. • Bowl-shaped surface is crafted of steel and wire mesh.
Radio Telescopes • Radio signals can be detected round the clock. • Radio signals coming from celestial bodies are week, so radio telescopes are usually built in valleys to shield from artificial radio waves. • E.g. of radio telescope • Arecibo telescope in Puerto Rico measures 305 meters across.
Radio Telescopes • Radio Interferometry • Links signals from two or more radio telescopes in separate locations for greater detail when observing. • The more telescopes added the greater the resolving power. • E.g. • VLA (Very Large Array) near Socorro, New Mexico. • A Y-shaped array of 27 dish-shaped antennas, • Each 25 meters wide and extending 21 km long.
ARECIBO RADIO TELESCOPE • The Arecibo Observatory in Puerto Rico contains the largest single stationary radio telescope in the world. • Because it remains stationary, the Arecibo telescope uses Earth’s rotation to turn its field of view across the sky. • Radio waves bounce off the bowl of the telescope and into the detecting platform suspended above the bowl.
RADIO MAP • The Parkes 64-m (210-ft) radio telescope in Australia produced this radio map of the Large Magellanic Cloud. • The colors of the image correspond to radio wave intensity; black is the least intense, red the most. • A radio map often reveals structures that are invisible to visible-light telescopes.
THE VERY LARGE ARRAY • Radio telescopes detect electromagnetic radiation from space in wavelengths ranging from about 1 mm (0.04 in) to more than 1 km (0.6 mi). • Since radio telescopes are only sensitive to electromagnetic radiation with a relatively long wavelength, signals from a group of telescopes pointing at the same object can be combined, dramatically improving resolution. • For example, the Very Large Array (VLA) in Socorro, New Mexico, has 27 dishes whose individual signals can be combined to form a single high-resolution image.
Infrared Telescopes • Permits scientist to explore dark dusty regions of space both within and beyond our galaxy to uncover clues about: • A. Birth of stars • B. Formation of planetary systems • C. Behavior of comets • D. Behavior of planetary atmospheres • E. Core of the Milky Way • F. and Birth of some of the most distant galaxies in the universe.
Infrared Telescopes • Infrared astronomy can be performed on • A. dry high-altitude observing sites. • B. Aircraft • C. Outer Space (Space telescopes) • Uses the basic design of optical telescopes but detector gathers only infrared light at the focus.
Infrared Telescopes • Image can be contaminated by • A. Atmospheric heat and • B. Heat produced by telescope itself. • Corrects the image by subtracting background information heat from final image. • Telescope is cooled to reduce heat contamination.
STELLAR NURSERY IN INFRARED • The Infrared Space Observatory (ISO) detected infrared radiation in space. • It could see through clouds of interstellar dust because infrared radiation is not blocked by the dust as much as visible light is. • The ISO took this picture of new stars forming out of a cloud of dust and gas. • The stars are not visible to optical telescopes because the visible light that they emit is blocked by the dust surrounding them.
INFRARED TELESCOPES • Infrared telescopes detect radiation that has wavelengths longer than the light that humans can see. • Infrared radiation enters the telescope and reflects off of a large mirror on the bottom of the telescope, then off of a smaller mirror. • Detectors and instruments beneath the mirrors record the radiation. • Infrared telescopes must be kept at very low temperatures to prevent their own heat from producing infrared radiation that could interfere with observations.
Ultraviolet Telescopes • Similar to optical telescopes but mirrors have special coatings that reflect ultraviolet light very well. • Provides much information about: • A. Interstellar gas • B. Young stars • C. Gaseous areas of active galaxies.
Ultraviolet telescopes • Some of the hottest and most energetic stars are visible in the ultraviolet light region of the spectrum. • E.g. • 1. International Ultraviolet Explorer (IUE) • 2. Extreme Violet Explorer (EUE) • 3. ASTRO space shuttle observatory • 4. Hubble Space Telescope (HST) • These four are Earth-orbiting observatories or telescopes.
X-ray Telescopes • Built like optical refracting telescopes. • The main mirror of these telescopes are nearly cylindrical. • Mirror shape lets light be reflected in shallow angles towards the detector. • To block untargeted x-rays, telescopes are surrounded with x-ray absorbing lead.
X-ray Telescopes • E.g. • 1. US space explorer 42 • 2. NASA Chandra X-ray Observatory • 3. ESA’s X-ray Multimirror System Mission mounted on high altitude rockets.
THE SUN IN X-RAYS • X-ray telescopes gather X rays just as optical telescopes gather visible light. • Hot gases in the sun produce X rays that an X-ray telescope can detect, creating an image such as the one pictured here.
CHANDRA X-RAY OBSERVATORY • This artist's impression depicts the Chandra X-Ray Observatory. • The orbiting observatory has detected many new astronomical X-ray sources and produced a wealth of high-resolution images of stars, nebulas, and galaxies.
SUN IN X-RAYS • X-ray telescopes gather X rays just as optical telescopes gather visible light. • Hot gases in the sun produce X rays that an X-ray telescope can detect, creating an image such as the one pictured here.
Gamma-Ray Telescopes • Consist of two or more Gamma ray detectors in a line. • Two detectors are placed in a line pointing to the source. • Gamma ray from the targeted source will pass through both detectors. • Detectors triggered by gamma ray passes through it, no matter what direction the gamma ray is travelling.
Gamma-Ray Telescopes • Some of the most catastrophic events in the universe, such as neutron star collisions and black holes, • Blast high energy gamma rays across space. • E.g. Compton Gamma Ray Observatory (GRO)
GAMMA-RAY TELESCOPE • A gamma-ray telescope detects radiation that has a shorter wavelength than visible light. • Gamma rays enter the telescope through the charged-particle detector and pass into layers of material that transform the gamma rays into electrons and positrons. • The electrons and positrons have electric charges, which cause sparks as the particles pass through the spark chambers in the lower part of the telescope. • Light detectors at the bottom of the telescope record the sparks.
