Tools of Modern Astronomy

Astronomy Chapter 3.1Pages 94-100

• Collect and focus different types of electromagnetic radiation

Telescopes

• Refracting • Reflecting

• Two convex lenses (thinner at the edges) gather large amounts of light and focus it into a small area.

• Galileo used one in 1609 to look at the sky• The larger the lens the more light it can

collect

Refracting Telescope

Refracting TelescopeLightRays

Focal Length

Of objective lens

Objective Lens

EyepieceLens

Reflecting Telescope• Uses a mirror instead of an objective lens• Larger mirrors capture more light• Newton built the first one in 1688• Today, this is the largest visible telescope.

Reflecting TelescopeLightRays

Flat Mirror

Curved Mirror

Eyepiece Lens

• Most have a curved surface 305m in diameter

• The surface concentrates the faint radio waves towards an antenna

• The larger the telescope the more it can collect.

Radio Telescopes

• Used to detect radio waves– Quasars (massive black holes that emits

intense radiation as it sucks in stars) and Pulsars (rotating neutron stars)

Radio Telescopes

• Used to analyze properties of light– Can be used to identify elements

Spectroscope

• Radio Detection and Ranging– Developed during WWII to detect enemy aircraft– Now commonly used to track weather formations

RADAR

• Uses beams of microwaves to actively detect objects in space

• Range is limited to our solar system.

• Long Wavelengths<--->Short Wavelengths• Radio/Infrared/Visible/UV/X-Ray/Gamma

Other Telescopes

Observatories• Building that contains

one or more telescopes• Most are built on

mountain tops– Less atmosphere and

less light pollution from cities

• Mauna Kea, Hawaii– 4,200 m above sea level

Observatories

• Free of Clouds• No light Pollution• Less Atmosphere

Satellites• Earth’s atmosphere blocks

out most of the short wavelengths on the Electromagnetic spectrum– UV, X-Ray and Gamma

Rays• Satellites can detect these

forms of radiation• Very detailed images

• Hubble Reflecting TelescopeCollects Infrared, Visible and UV radiation

• Chandra X-Ray ObservatoryDetects X-rays.

Satellites

What to Work On• Begin Chapter 2 Unit Review

Pages 90 and 91• Answer as many questions as you can

Give the page number you found the answer on