Download EM spectrum telescopes,HR star info-domenico

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
• http://www.colorado.edu/physics/2000/waves_particles/index.ht
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 1970’s.
• 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
#waves/time = cycles/sec = Hertz (Hz)
• Long wavelength = low frequency
• Short wavelength = high frequency
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 1980’s.
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 Hawaii’s 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