Observing over the entire electromagnetic spectrum
• Different phenomena produce different wavelength waves
– Ordinary stars:  Visible light
– Cool planets or dust clouds:  Infrared light
– Moving charged particles, cool molecules:  Radio waves
– Very hot objects:  X-Rays and Gamma Rays
– Quasars: ALL wavelengths
• Only visible, some IR, and radio make it through
atmosphere
– Need to observe from space for other wavelengths
• Going into space also lets you obtain more detailed images
– On Earth telescope size isn’t only limit on image resolution
– Temperature fluctuations in atmosphere cause “seeing” (blurring)