1. Telescopes 4/23/15 IN: What is a telescope? How is it used?
18-3 pgs
IN: What is a telescope? How is it used?

2. Telescope – an instrument that collects electromagnetic radiation from the sky and concentrates it for better observation.

3. Electromagnetic spectrum – all the wavelengths of electromagnetic radiation.
From stars.

5. Multiwavelength Astronomy - Our Galaxy: The Milky Way

9. Refracting telescope – uses a set of lenses to gather and focus light.

10. Refracting telescope
Size is limited
Large lens can distort image

11. Reflecting telescope – uses curved mirrors to gather and focus light.

12. Reflecting telescope Mirrors can be made very large
Allow all colors to be seen.

13. Very Large Reflecting Telescope
Keck Telescope, Hawaii

14. Optical Telescopes and the Atmosphere
The light gathered can be affected by the atmosphere.
The dust and dirt in the atmosphere is what cause stars to “twinkle”.

15. Optical Telescopes and the Atmosphere
Telescopes are place in dry areas to avoid water vapor in the air.
Mountaintops are also good places because or the higher elevation.
This puts the telescope above pollution and increases the visibility of stars.

16. Hubble Space Telescope
To avoid the atmosphere, scientists put telescopes in space.
Hubble Space Telescope
hubblesite org

17. Non-Optical Astronomy
Astronomers are interested in all forms of electromagnetic radiation because different objects radiate at different wavelengths.
Radio Telescopes
Receive radio waves
Hopkins Telescope
Detects UV wavelenghs

31. OUT: Name one way in which refracting and reflecting telescopes are similar and one way they are different.