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How to Make a Simple Telescope That Does Not Cost a Lot

Astronomers use powerful telescopes to get closer views of the moon, stars and other celestial bodies. Everyday people also use telescopes to observe the night sky. Telescopes use lenses that work in cooperation to focus on an object and magnify it so that the eye sees it as a larger image. Telescopes range in size and magnifying strength and can range greatly in price. This optical experiment allows you to make a simple refractor telescope using inexpensive household materials.

Things You'll Need

2 lenses
1 piece of cardstock
1 paper towel tube
Masking tape

Instructions

- 1
  Purchase two different sized lenses from a craft or hobby store. One of the lenses must be convex, meaning that it is thicker in the center than it is at the edges. The other of the lenses must be smaller and can be either convex or concave. Concave lenses are thicker at the edges than in the middle.
- 2
  Cut a piece of cardstock so that is a little wider than a paper towel roll is long. Roll it up to fashion a tube that has approximately the same diameter as the smaller of the two lenses that you purchased. Tape this smaller lens to one end of the tube to form the eyepiece lens.
- 3
  Use a convex lens for the eyepiece to make objects appear upside down. Scientists call this type of scope a Galilean scope. Use a concave lens to see things right side up. Scientists refer to this as a Newtonian scope.
- 4
  Use tape to secure the larger convex lens to the end of a paper towel tube to form the objective lens. The objective lens will collect light from the objects that you point it at. Slide the other end of the paper towel roll into the cardstock tube.
- 5
  Look through the completed refractor telescope, pointing it at a distant object. The eyepiece lens will take the light collected by the objective lens and enlarge it so that your eye will see the object several times larger.

Astronomy