1. Telescopes

2. Galileo 1609

3. The Moon as a World

4. Jupiter has Moons

6. Refracting telescopes

8. Isaac Newton’s reflecting telescope

9. Reflecting telescope Objective mirrors instead of lenses

10. Three Powers Magnifying Resolving Light Gathering

11. Magnifying Power Ability to make objects appear larger in angular size One can change the magnifying power of a telescope by changing the eyepiece used with it Mag Power = focal length of objective divided by the focal length of the eyepiece

12. Resolving Power Ability to see fine detail Depends on the diameter of the objective lens or mirror

13. Light Gathering Power The ability to make faint objects look brighter Depends on the area of the objective lens or mirror Thus a telescope with an objective lens 2 inches in diameter has 4 times the light gathering power of a telescope with a lens 1 inch in diameter

14. Herschel & Lord Rosse

15. 19 th century: epoch of the large refractors

16. Refracting telescopes Vienna Lick

17. Yerkes Observatory

18. 20 th century Large Reflectors Come of Age Mount Wilson

19. Palomar (5-m)

20. 4 meter Reflecting telescope

21. Objective Mirror

22. Dome of 4 meter Kitt Peak

23. Keck Telescopes

24. Rooftop telescopes

25. MSU Campus Observatory

27. SOAR Telescope

28. SOAR Telescope -- Cerro Pachon

29. Astronomical “seeing” Blurring effect of looking through air Causes stars to twinkle

30. Bad seeing on this side Good seeing on this side

31. Electromagnetic Spectrum

32. Radio Telescopes Arecibo

33. Very Large Array

35. Observing from space No clouds Perfect seeing Can see wavelengths of light blocked by the earth’s atmosphere

36. Hubble Space Telescope