Light and Telescopes

ASTRONOMY

LIGHT AND TELESCOPES

Chapter 3

Key Terms

·  Photons

·  Electromagnetic radiation

·  Electromagnetic spectrum

·  Active optics

·  Adaptive optics

·  Angular resolution

·  Magnification

·  Objective lens and eyepiece

·  Reflecting telescope

·  Refracting telescope

·  Redshift vs. blueshift

·  Doppler Effect

·  Spherical aberration

·  Chromatic aberration

·  Light-gathering power

·  Charged-coupling device (CCD)

·  Light pollution

·  Seeing and twinkling

·  Interferometry and very-long-baseline interferometry

·  Primary and secondary mirrors

Essential Questions

1.  How can the study of light help astronomers understand the objects in the universe?

2.  How does an astronomer decide which telescope best suits the object that they are studying?

General Questions

Electromagnetic Radiation (3-1 through 3-4)

1.  What are the seven types of light associated with the electromagnetic spectrum?

2.  What is the speed of light?

3.  What is the dual nature of light?

4.  What is the difference between frequency and wavelength?

5.  What is the relationship between vibrational frequency of light and temperature?

6.  What causes redshifting and blueshifting?

Telescopes (3-5 through 3-9)

1.  What are the main parts of a reflecting telescope?

2.  What are the main parts of a refracting telescope?

3.  How does a reflecting telescope produce an image?

4.  How does a refracting telescope produce an image?

5.  What limitations exist with the reflecting telescope?

6.  What limitations exist with the refracting telescope?

7.  What is angular resolution?

8.  What is the significance of light-gathering power?

9.  How can the angular resolution (or sharpness) of the image be improved?

10.  How do you determine the magnification of a telescope?

11.  What is a CCD and why is it so useful?

Seeing the Sky on Earth (3-10)

1.  What hinders our view of the sky when using a land-based telescope?

2.  What is light pollution?

3.  What conditions need to be met for good seeing?

4.  Which types of light associated with the electromagnetic spectrum cannot be viewed on Earth? Why?

5.  Telescopes on Earth are designed to capture which two types of light?

6.  Where would be the best location for a visible-light telescope on Earth?

Space-Based Telescopes and Non-Optical Astronomy (3-11 through 3-15)

1.  What makes the Hubble telescope such a valuable tool for astronomers?

2.  Which type of light does the Hubble telescope observe?

3.  What is active optics? What is adaptive optics?

4.  What is inferometry?

5.  How do astronomers improve the angular resolution of land-based radio and visible light telescopes?

6.  Why do astronomers need space-based telescopes?

Ch. 3 Learning Targets (Monday, September 29, 2014)

1.  I can explain the conditions that constitute good seeing when using a telescope.

2.  I can identify the problems associated with viewing the night sky using a telescope.

3.  I can define angular resolution and how it relates to telescopes.

4.  I can identify the three functions of a telescope and the relative importance of each.

5.  I can depict strategies to improve the view of the night sky if using a telescope.

6.  I can calculate the magnification of a telescope.

7.  I can explain problems associated with the lens for a refracting telescope and the mirror for a reflecting telescope.