1. Telescopes

2. Telescopes Key Concepts
What are the regions of the electromagnetic spectrum?
What are telescopes and how do they work?
Where are most large telescopes located?

3. Telescopes - Key Terms Telescope Electromagnetic radiation
Visible light
Wavelength
Spectrum
Optical telescope
Refracting telescope
Convex lens
Reflecting telescope
Radio telescope
Observatory

4. Telescope A device that makes distant objects appear to be closer.
Galileo made the telescope famous.
He was the first to see sunspots, Saturn’s Rings, and the four large moons of Jupiter

5. Electromagnetic Radiation
Energy that can travel through space in the form of waves
Examples of Forms of Radiation
visible light – radiation you can see
infrared – feel as heat
radio waves

6. Ranges from long wavelength radio waves to short wavelength gamma rays

7. Types of Telescopes Instruments that collect and focus
light and other forms of electromagnetic radiation.
Optical telescope – uses lenses or mirrors to collect and focus visible light
Two types – refracting and reflecting
Non-optical – Use other forms of electromagnetic radiation such as radio waves, x-rays and gamma rays

8. Refracting Telescopes
Uses convex lenses to gather and focus light
Convex lens is a curved piece of glass that is thicker in the middle than the edges
The larger the lens the more light the telescope can collect
Simple refracting telescope has 2
lenses – the objective lens and the eyepiece lens
Yerkes Telescope in Wisconsin is the largest refracting telescope

9. Reflecting Telescopes
Isaac Newton built the first in 1668
Uses a curved mirror to collect and focus light
The larger the mirror, the more light that can be collected
Largest optical telescopes today are reflecting

10. Radio Telescopes Devices used to detect radio
waves from objects in space
Most have curved reflecting surfaces that focus radio waves the way the mirror does in reflecting telescopes
Concentrate the faint radio
signals onto small antennas like those on radios
Ex. The Very large Array, Arecibo

11. Other Telescopes Detect: Infrared – Spitzer Space Telescope
Ultraviolet
X-rays – Chandra X-Ray Observatory
Gamma rays
Hubble Space Telescope detects
visible, ultraviolet, and infrared

12. Observatories
A building that contains one or more telescopes. (some in space)
Many large observatories located on mountaintops or in space – atmosphere makes images blurry.
Radio telescopes are not affected by atmosphere