1. Light and Telescopes

2. A Telescopes is a tool used to gather light from objects in the universe

3. Tool
Websters: Tool- something (as an instrument or apparatus) used in performing an operation or necessary in the practice of a vocation or profession
From the Urban Dictionary: Tool - One who lacks the mental capacity to know he is being used. A fool. A cretin. Characterized by low intelligence and/or self-steem.

4. There are two different types of telescopes
A refracting telescope uses a glass lens to concentrate incoming light
A reflecting telescope uses mirrors to concentrate incoming starlight

5. A refracting telescope uses a lens to concentrate incoming light

6. Reflecting telescopes use mirrors to concentrate incoming starlight

7. Three main functions of a telescope
Most important!!
Gather More Light – (bigger Is better) making objects appear brighter
followed by
to see fine detail
(called resolution)
and least important,
magnify
magnification = (objective lens focal length / eyepiece lens focal length)

8. A larger objective lens provides a brighter (not bigger) image

9. If you pass white light through a prism, it separates into its component colors.
long wavelengths
ROY G B I V
short wavelengths
spectrum

10. But visible light is only one type of electromagnetic radiation (light) emitted by stars
Astronomers are truly interested in the entire spectrum of Light!

15. Consider This Class as Seen in Different Wavelengths of Light!

16. Consider Orion as Seen in Different Wavelengths of Light!

17. Observations at other wavelengths are revealing previously invisible sightsUV
infrared
Map of Orion region
Ordinary visible

18. Hubble Space Telescope Views of Orion Nebula showing stars hidden in clouds

19. TODAY’S Sun as seen in visible light from Earth and from space in X-rays by satellites

20. Radio wavelength observations are possible from Earth’s surface

21. The Very Large Array (VLA) in New Mexico

23. Earth’s atmosphere hinders astronomical research
Image of stars taken with a telescope on the Earth’s surface
Same picture taken with Hubble Space Telescope high above Earth’s blurring atmosphere

24. High above Earth’s atmosphere, the Hubble Space Telescope provides stunning details about the universe

25. Astronomers use different instruments to look at light of different wavelengths - sometimes, we even have to go above Earth’s atmosphere.

31. Not all EM radiation can penetrate Earth’s atmosphere.

32. Why do stars twinkle, but planets seemingly do not?

33. Differences in the temperature and density of small portions of Earth’s atmosphere cause passing starlight to quickly change direction, making stars appear to twinkle.