The Electromagnetic Spectrum and information from the Stars X-ray image of the sun

Electomagnet (EM) Specrtrum All radiation, radio wave and light are part of the EM spectrum Visible light is only a very small section of the whole spectrum

Simpler version of the EM spectrum

Wavelength- Distance covered by one full cycle of a wave- commonly measured crest to crest CU physics site animation shows wavelengths mlhttp:// ml

Relative size of wavelengths

Arecibo The Arecibo radio telescope in Puerto Rico is the largest single dish telescope in the world. This 1000 foot dish was constructed over a natural crater. (= 0.3km = 0.2 mi)

Radio antenna and radio telescopes are large to pick up long wavelengths

VLA The very large array in Socorro New Mexico was built in the 1970s. It uses 27 radio telescopes all linked together in a Y shape. These telescopes simulate a large radio telescope 40 km in diameter.

The SETI Project SETI stands for the Search for Extraterrestrial Intelligence. SETI began using the Arecibo telescope to look for alien signals. In 1974 the Arecibo telescope sent a megawatt signal to outer space.

Frequency- How often a complete wave passes a set point Long wavelength = low frequency Short wavelength = high frequency #waves/time = cycles/sec = Hertz (Hz)

Energy in the wave Long wavelength = low frequency = low energy Short wavelength = high frequency = high energy

Fill in your own chart:

Spectra are created from excited electrons in atoms Valence electrons absorb energy from heat, electricity, other EM emissions Electrons jump up to a higher energy level When electrons fall back to ground state they give off EM emisions

Kinds of spectrum Continuous spectrum- like the rainbow Absorbtion Spectrum - has rainbow with black lines in it Emmission spectrum – just a line or two or three…………. Of colored light

Types of Galaxies- draw in Elliptical Spiral Irregular

Doppler Effect Red Shift-move away –Lengthen wavelength –Color shifts toward red end Blue shift-move toward –shorten wavelength –Color shifts toward blue end

Mass of the universe determines fate More than critical mass collapse Big Crunch another Big Bang? Does the universe occilate? Closed universe Less than critical mass expands forever Open universe

HR diagram Graphs stars Temp (color or spectral class) vs Absolute magnitude (Luminosity) Absolute magnitude – brightness based on being the same distance away from each star Apparent magnitude – brightness from Earth- all stars are different distances away

HR Diagram Temp degrees C

Put colored stars of appropriate size on your chart

Layers of the Sun

Micro-Wave & Infra-Red Telescopes

2 Famous Telescopes In the 1960 Robert Wilson & Arno Penzias won the Noble Prize for their discovery with the first large microwave telescope. COBE was a microwave / infra-red satellite in the 1980s.

Visible Optical Telescopes Early history of optical telescopes. Modern day observatories. The future of optical telescopes.

Yerkes Observatory Built in 1897 the Yerkes telescope in Wisconsin is the largest refractor. It has 40 inch diameter lens!

The Mt. Wilson Hooker Telescope In 1908 the largest reflector telescope was built on Mt. Wilson overlooking Los Angeles. This Hooker telescope uses a 100 inch mirror to collect light.

The Palomar Observatory, Hale Telescope In 1948 the largest telescope was the 200 inch Hale telescope on Palomar Mountain, California.

The BTA Telescope Currently the largest single mirror telescope is the BTA, (Bolshoi Teleskop Azimutal) in Southern Russia. The BTA was built in 1975 and uses a single 230 inch mirror to collect light!

Multiple Mirror Telescopes After building the huge BTA telescope, astronomers realized that 200 inches is the maximum size for a telescope. Anything larger than 200 inches and the mirror becomes distorted under its own weight. The solution to this problem was to build multiple mirror telescopes.

Multiple Mirror Telescopes M.M.T. combine many mirrors to form one giant mirror. These mirrors are computer controlled to make a parabolic shape. The KECK telescope in Hawaii is currently the largest telescope in the world with a total of 400 inches of segmented mirrors!

3 Famous Observatories #1 Mauna Kea is Hawaiis tallest peak and home to the largest telescopes in the world. #2 Las Campanas Chile has some of the clearest seeing on the the planet. #3 Kitt Peak Observatory in Tucson Arizona has a large collection of telescopes.

Mauna Kea, Hawaii

Las Campanas, Chile

Chile

The European Tel. In Chile

Kitt Peak, Tucson Arizona

Current Problems Aside from money, two of the biggest problems facing optical observatories are: 1. Light Pollution 2. Atmospheric turbulence

The Hubble Space Telescope By placing a telescope in orbit you solve the problems of light pollution and atmospheric turbulence. In 1990 the space shuttle Discovery was launched with the 90 inch Hubble Space Telescope.

The Future of Optical Telescopes The NGT (Next Generation Telescope) will be a 300 inch multiple mirror orbiting space telescope. The ELT will be a 30 meter (3 times larger than the Keck) segmented mirror telescope.

2 Plans for the NGT

LBT Large Binocular Telescope

One of the LBT mirrors

GSM Giant Segmented Mirror

ELT Extremely Large Telescope

Ultra-Violet Telescopes UV telescopes must observe from outer space. These telescopes specialize in observing the sun. The IUE is the International Ultra-Violet Explorer space telescope.

The IUE

The sun through the IUE

X-Ray Telescopes X-Ray telescopes study high energy objects like black holes. The Chandra X-Ray telescope was launched into space two years ago.

The Chandra X-Ray telescope

The Sun in X-Rays

Gamma Ray Telescopes Gamma Ray telescopes study very high energy objects like gamma ray bursters and supernova explosions. The Compton Gamma ray telescope was the most famous of these telescopes.

Compton Gamma Ray Telescope

The End