1. Radiation & Telescopes ____________ radiation: Transmission of energy through space without physical connection through varying electric and magnetic fields Example: __________

2. Wave Motion Label the Wave How we see light video

3. _____________: Number of wave _______ that pass a given point per second __________: Time between passage of successive crests Relationship: Period = 1 / Frequency

4. Wavelength: ___________ between successive _________ Velocity: __________ at which crests move Relationship: Velocity = ____________ / ________

5. No limit on wavelengths; different ranges have different names Note opacity of atmosphere Light and Color Bill Nye Video Part I

6. Waves The Speed of Light in Glass Video The Speed of Light in Glass Video Water waves, sound waves, and so on, travel in a ________ (water, air, …) Electromagnetic waves need ____ ____________ Created by accelerating _________ particles

7. What is the wave speed of electromagnetic waves? c = 3.0 x 10 8 m/s This speed is very large, but still finite; it can take light __________ or even __________ of years to traverse astronomical distances

8. Telescopes ____________ lens

9. Images can be formed through reflection or refraction _____________ mirror

10. Modern telescopes are all _______________: Light traveling through lens is refracted differently depending on ____________ Some light traveling through lens is absorbed Large lens can be very _________, and can only be supported at edge A lens needs two optically acceptable surfaces; mirror needs only one

11. Types of reflecting telescopes

12. The two 10-m telescopes of the Keck Observatory. (b) Artist’s illustration of the telescope, the path taken by an incoming beam of starlight, and some of the locations where instruments may be placed. (c) One of the 10-m mirrors. (The odd shape is explained in Section 5.3.) Note the technician in orange coveralls at center. (W. M. Keck Observatory) The Keck telescope a modern research telescope

13. Sunrise on Mauna Kea in JuneMauna Kea

15. The _______ Space Telescope has a variety of detectors

16. Hubble Telescope image before and after it was fixed

17. Here we compare the best ______________ image of M100, on the left, with the ______ images on the right

18. Size _________________ power: Improves detail Brightness proportional to square of radius of mirror Photo (b) was taken with a telescope twice the size of the telescope that took photo (a)

19. Size Resolving power: When better, can distinguish objects that are closer together Resolution is proportional to wavelength and inversely proportional to telescope size— bigger is better!

20. Figure 5-12. Detail becomes clearer in the Andromeda galaxy as the angular resolution is improved some 600 times, from (a) 10’, to (b) 1’, (c) 5”, and (d) 1”. (Adapted from AURA)

21. Atmospheric ___________ is due to ______ movements

22. Solutions: Put telescopes on _____________, especially in __________ Put telescopes in _________ Why is it Dark at Night video

23. ________ telescopes Similar to optical reflecting telescopes Prime focus ______ sensitive to imperfections (due to ______ wavelength); can be made very _______ Largest radio telescope is the 300- m dish at _________

24. ________ wavelength means ________ angular resolution Advantages of radio astronomy: Can observe ____ hours a day Clouds, rain, and snow _______ ____________ Observations at an entirely ____________ frequency; get totally different ____________

25. Space Based Infrared radiation can produce an image where visible radiation is __________; generally can use optical telescope mirrors and lenses

26. _________ telescopes can also be in space; the image on the top is from the Infrared Astronomy Satellite

27. The __________ Space Telescope, an ___________ telescope, is in orbit around the Sun. These are some of its images.

28. Ultraviolet observing must be done in ______, as the atmosphere absorbs almost ______ _____________ rays.

29. ________ image of ___________ remnant __________ rays cannot be ____________ at all; images are therefore __________

30. Full-Spectrum Coverage Figure 5-36. Multiple Wavelengths The Milky Way Galaxy as it appears at (a) _____, (b) infrared, (c) ______, (d) X-ray, and (e) ____________ wavelengths. Each frame is a panoramic view covering the entire sky. The center of our Galaxy, which lies in the direction of the constellation Sagittarius, is at the center of each map. (NRAO; NASA; Lund Observatory; MPI; NASA)