Luann Keplinger, age 10h, of Roseville, Minnesota, for her question:

Which is the world's largest telescope?

There are two types of telescope    and champions of each kind are in the United States. The simplest kind is the refracting telescope. It may be a beginner's tele¬scope that magnifies about 30 times or a large model in an observatory that makes the faraway stars look hundreds of times bigger. If you train a beginner's model on the moon, the picture you see is upside down. On larger models, they have as extra gadget to turn it right way up again. The world's largest refracting telescope is at Williams Bay, Wisconsin, in the Yerkes Observatory.

The other type is the reflecting telescope that magnifies with the help of a mirror. It can be much larger and reach much farther out into space. The largest reflecting telescope is at Palomar Observatory in California. It is called the Hale telescope and its huge reflecting mirror is 200 inches wide. The lens of the largest refracting telescope is 40 inches wide.