Homework
Activity 6a Gathering Starlight, Experimenting with Aperture

1. Explain how many people can see the same star in the sky even though the star looks like only a pinpoint of light.
2. Sketch two telescope setups, each with a different aperture.

3. Think about gathering starlight.
1. What do you think the advantage is in having larger aperture telescopes?
2. Do you think there are any disadvantages to a larger aperture telescope?
4. The experiment for aperture compares images taken with the same telescope, but with a mask put over the telescope with an opening that can be varied in size.  This creates a telescope that has the same focal length but a variety of options for aperture.  What changes as we cover or open more of the telescope to the night sky?  What does not change?
   
5. Why was it important to take images with each aperture on the same night and one right after another? 

This wooden cover fits over the telescope tube opening on the 24 inch telescope at Yerkes Observatory.  The center portion does not allow any light to pass through because it fits around the secondary mirror mount.  There are two 8 inch openings. One is covered by a piece of poster board.  The other can be  covered by masks with 2 inch, 4 inch, and 6 inch diameter openings.

We used this setup to image the same objects without the mask for a 24 inch aperture diameter telescope, and then with the variety of masks to make 2 inch, 4 inch, 6 inch, and 8 inch aperture diameter telescopes.