Course Icon

Chapter 6 Homework

Course Materials are always under revision! Weblecture content may change anytime prior to two weeks before scheduled chat session for content.

SO Icon


Scholars Online Astronomy - Chapter 6: Optics and Telescopes


Reading Preparation

Reading: Astronomy, Chapter 6: Optics and Telescopes

Study Notes: notes on your assigned reading from the text

Key Formulae to Know

  • Magnification of telescope M: M   =   F Objective F Eyepiece
  • Light Gathering Power P: P     D 2
  • Angular Resolution θ: θ   =   2.5     10 5   λ D

Web Lecture

Read the following weblecture before chat: Telescope Basics

Study Activity

  • Planetarium exercise: If your planetarium program models different telescopes, select at least three (use a low powered binocular, a 4" and an 8" refractor if possible) and compare the field of view, magnification, and quality of image provided by each. Use each to view the Moon (pay attention to details along the terminator and crater definition), Saturn (pay attention to the rings!), and Jupiter (pay attention to the moons!). Identify the smallest crater on the Moon where you can see both sides as distinct. Estimate the resolution of each telescope.

    If you are not able to use a planetarium program use the telescope simulator at Stelvision. Enter the diameter of the telescope for

    • binoculars: 60 (about 2.3" -- this is he smallest value allowed)
    • small telescope: 100mm (about 4")
    • large telescope: 203mm (about 8")

    With each telescope, view the moon. Remember that the Moon is about 31 arcseconds. Use this information to estimate the field of view diameter.

    Use the detailed simulator with your 203mm telescope setting and vary your eyepieces. How does magnification change?

  • Optional Websites: Compare the visible light view of the "Cigar galaxy" (M82) with the infrared view taken by NASA's Spitzer Space Telescope. What can you see in the white-light picture that isn't visible in the infrared? What can you see in the infrared that isn't visible in the white-light picture? How does our theory of light emission explain the difference? What do the differences tell you about the composition, shape, and temperatures of this galaxy?

Chat Preparation Activities

Chapter Quiz

Lab Work

Read through the lab for this week; bring questions to chat on any aspect of the lab, whether you intend not perform it or not. If you decide to perform the lab, be sure to submit your report by the posted due date.