Telescope workshop

for Astronomy & Cosmologies, spring 2013

by Dr. E.J. Zita, The Evergreen State College
Adapted from Grinnell optics workshops, Phil Pearl's thin lens workshop, and Dale Ferguson's telescope workshop.
Goals    Overview     Equipment      Details (A, B, C)

This workshop is designed to show you how lenses affect light. By bending light rays, lenses can focus light (onto camera film...), form images (on your retina...), defocus light (useful in some corrective lenses), and change the sizes of images (telescopes, microscopes...)  Lenses let us more clearly see objects that are too distant or too small for naked eyes.  Lenses in telescopes help bring the stars to Earth.

Do parts A and B below;  leave C for the very end in case you have extra time, maybe design some investigations of your own... and turn in the survey before you leave. Have fun!

Learning GOALS:


(A) Make an image:  By holding a lens at the window or in the shade, and placing a screen behind the lens at the focal distance, you can see that a real image of an illuminated object appears on the screen.

(B) Make a telescope:  If you remove the screen, the real image is still there in space, and it can be examined with a magnifying glass. That is a telescope.

(C) Further investigations:  Play with different lenses.  If you have time, investigate how the relative positions (and focal lengths) of lenses affect image locations and sizes, more carefully and quantitatively.