Light, Optics and Telescopes

The Electromagnetic Spectrum

Photons of different energies radiate at different wavelengths or frequencies

wavelength x frequency = velocity of light ( c)

= c

c = 5 x 105 km/s

c = 186,000 miles/s

Atmospheric Windows

Visible and radio

Physical Properties of Light

Refraction

Reflection

Refraction is wavelength dependent

Formation of an image

Telescopes -- Refractors

Yerkes Observatory – Lake Geneva, Williams Bay Wisconsin

20th Century Large Reflectors

Mt Wilson 100-inch – 100 yrs old

Cerro Tololo 4 -meter

Palomar 200-inch

Modern Observatories

Cerro Tololo Interamerican Obs.

Kitt Peak National Obs.

Tucson Arizona

Very Large Telescopes Mauna Kea

ESO – VLT

MMT on Mt. Hopkins, AZ

Minnesota’s $5M (private) investment in a very large telescope (> $100M)

Large Binocular Telescope (LBT) Mt. Graham Arizona

Design

Other partners -- University of Arizona, Germany, Italy, Ohio State University, University of Virginia, Notre Dame

Radio Telescopes

Arecibo

Very Large Array – VLA

Telescopes in Space -- other wavelengths – UV, X ray, gamma ray and far-IR