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

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

20 th 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