1. TELESCOPES

2. Telescopes Write what is in YELLOW
You will be accountable for text in yellow on quizes.

3. Where do we put telescopes to have the best viewing conditions?
1. On Earth:
CLEAR
HIGH
DRY
COLD
DARK

4. Problem with Telescopes on Earth?
Particles of all sorts in the atmosphere block and cloud the view

5. 2. In Space Solves atmosphere problem – CLEAR VIEW!
Examples: Hubble, Cobe , Iras

6. Problem with telescopes in space?
They’re in space!
Hard to get to
Hard to repair
EXPENSIVE!!!

7. Functions of a Telescope
Collect Light
Magnify Images
Separate Distant Objects
Use as a Camera

8. I. OPTICAL TELESCOPES (USE VISIBLE LIGHT)
Two types:
Refractor – BENDS LIGHT
Invented by Hans Lippershey in 1608
Refined by Galileo in 1609

9. Galileo demonstrating his telescope

10. Tololo Observatory - Chile

11. TYPE 1 – REFRACTING TELESCOPE
How does it work?
It bends light to create an image
It uses two lenses
1. eyepiece (ocular) lens - small
2. objective lens - large

12. Draw it!

13. Type 2 – Reflecting Telescope
Invented by Isaac Newton in 1668
Uses two mirrors
Objective Mirror – Large
Secondary (flat) mirror – Small
c. Can be VERY LARGE 40 ft ft
diameter objective mirror!

14. 2. Reflector –
USES MIRRORS
Cheap and common

15. Draw It!

16. Most Modern Telescopes combine technologies
Examples
Hubble
Kepler -

17. Advantages of a reflector
only one side of the mirror.
(on a refractor the lens has two sides) – cheaper and distortion is less of a problem.
The whole back of the mirror can be supported, therefore can be made very LARGE

19. II. Non-optical Telescopes
Radio Telescopes
a. Location – Earth
(atmosphere does not affect radio waves)
b. Structure – Large metal dish

20. c. Size – very large because radio waves have a very long wavelength

21. d. Arrays – sets of multiple radio telescopes that allow for more data to be gathered.

22. Ex – VLA (very large array) in Socorro, New Mexico 27 dishes.
SETI– Search for Extra-Terrestrial Intelligence
looking for intelligent radio signals

23. Other Non-Optical Telescopes (all are satellites)
2. Infrared – IRAS launched 1983

25. 3. Microwaves – COBE Cosmic Background explorer
3. Microwaves – COBE Cosmic Background explorer. Discovered evidence of the Big Bang. Launched 1981

26. COBE Image of CBR

27. 4. X-Rays – Chandra Launched 1999

28. Cassiopeia Super Nova

29. Black Hole

30. Crab Nebula

31. Saturn

32. 5. Gamma Rays – GRO Gamma Ray Observatory

33. Milky Way