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How to Make an Improvised Telescope

Telescopes were first invented in the 16th century; over the years that followed they came to play a vital role in both astronomy and warfare. Today the world's largest telescopes have apertures measured in meters and enable astronomers to study distant objects like galaxies and quasars. You may not have the resources to build a telescope the size of the Hubble or the Keck, but improvising a rudimentary telescope is fun and relatively simple to do. If you feel ready for a more ambitious project once you're done, check out the Resources section below.

Things You'll Need

Two convex lenses of different size and magnifying power (the lenses from two magnifying glasses will work)
Two cardboard shipping tubes, one larger than the other
Cardboard
Duct tape

Instructions

- 1
  Estimate the focal length of the larger lens (the objective) by using it to focus sunlight onto the pavement (not onto flammable material) and moving it up or down until the light focuses to a single bright point. The distance between the ground and the lens is the focal length.
- 2
  Cut a hole in the end of the larger of the two cardboard mailing tubes; make it almost the size of the larger lens. Attach the larger lens securely to the end using duct tape.
- 3
  Remove the plastic end caps of the small mailing tube if it has them. If not, cut out the one end and cut a hole in the other a little smaller than the size of the small lens (the eyepiece lens).
- 4
  Cut out a couple pieces of cardboard that are roughly the diameter of the large mailing tube and cut a hole in each the size of the small mailing tube. Insert the small mailing tube into these pieces of cardboard (they should be near the end of the tube a couple inches or so apart) and tape or glue them on securely.
- 5
  Check the length of the two mailing tubes combined; it should be greater than the focal length of your objective but not more than three times the focal length or it may be difficult to focus properly. Trim a little off one end of the smaller mailing tube if necessary.
- 6
  Tape the eyepiece lens securely to the other end of the small mailing tube (opposite where the pieces of cardboard are attached).
- 7
  Remove the plastic cap from the end of the large mailing tube and insert the small mailing tube into it. Point your telescope at a distant object and move the small mailing tube further into the large one until the object is in focus.

Astronomy