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

•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.

THE VERY LARGE ARRAY

ARECIBO RADIO TELESCOPE

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

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

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• 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.

CHANDRA X-RAY OBSERVATORY

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.

THE SUN IN X-RAYS

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

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.

End of Presentation