| A simple telescope made from cardboard tubes. The top part slides into the bottom part. The length depends on the strength of the reading glasses and of the little lens which serves as the eyepiece. The total length should be approximately the sum of the 2 focal lengths. |
|
|
|
The magnification is equal to the ratio of the focal lengths.
Therefore, you want to find reading glasses with a long focal length
(weaker reading glasses), and an eyepiece lens with a short
focal length (such as a small magnifying glass).
|