|
|
Optical Powers
|
|
|
|
Optical Powers
|
|
| Name | |
| Class | Date |
Project: Model the amount of light which can pass through various telescope apertures with paper circles and dots. Compare the number of dots to the area of each circle.
1. Cut out circles with a diameters of 2, 4, 6, 8 and 24 inches..
2. Calculate the area of each of the circles and a paper-punch dot.
3. For each circle, predict how many paper punch dots will completely fill the circle.
4. Find out how many dots actually fit inside each circle.
5.
Complete the chart below.
| Calculate Area | Circle Size (Aperture) |
# Prediction |
# Actual |
# of Dots Class Average |
|
|
Paper
Dot |
|
|
|
|
|
2
inch |
|
|
|
|
|
4
inch |
|
|
|
|
|
6
inch |
|
|
|
|
|
8
inch |
|
|
|
|
Subtract
area of central obstruction. |
24
inch Do
not put dots over the central
obstruction. |
|
|
|
This is the mask for the Yerkes 24 inch telescope. The whole circle of wood fits over the end of the telescope. The center area fits around the back of secondary mirror holder, so no light gets through to the telescope's primary mirror from the center opening. Two 8 inch holes are cut out on either side of mask. One is completely covered by black square of poster attached with Velcro. The other side is either left open for an 8 inch opening or covered by masks with 2 inch, 4 inch or 6 inch openings. (This 'quick focus' mask is usually used to find the focus of the telescope. Out of focus results in two images; in focus results in one image. We used this mask in order to create the various aperture openings for imaging experiments.)
