If you're a budding astronomer, you'll be pleased to know you don't have to spend big bucks on a fancy telescope. Instead, you can make your own simple 9x magnification Galilean telescope at home. It's affordable yet powerful enough to see many of the wonders the sky has to offer. With a focus of 9x, this powerful homemade telescope lets you see features on the Earth's moon and Saturn's rings as a disk.
Things You'll Need
- Cardboard telescoping mailing tube with a diameter of 50 mm and a length of 1,100 mm
- Concave-convex lens (the objective lens) with a diameter of 49 mm and a focal length of 1,350 mm
- Plano-concave lens (the eyepiece) with a diameter of 49 mm and a focal length of 152 mm
- Coping saw
- Box cutter
- Drill or electrician's punch
Purchase the lenses from a specialty supply store. Find cardboard telescoping mailing tubes in an office supply store.
Remove the inner tube from the telescoping mailing tube. Using a coping saw, cut two pieces, approximately 2.5 to 4 centimeters, from the inner tube. This creates spacers to hold the objective lens.
Use a drill or electrician's punch to make an eyehole in the center of the removable cap on the end of the outer tube. Apply light pressure for a smooth cut.
Drill small holes on the outside of the inner tube and place the flat end of the eyepiece lens next to the removable cap. Push the lens and cap into the outer tube. Insert glue into the holes and rotate the lens to spread the glue. Hold the tube against the lens until the glue sets and then place to one side.
Cut the closed end of the outer tube. Work out how far into the tube the lens and spacers should be, then drill small holes around this spot. Insert the first spacer and apply glue to the corresponding holes, moving it to spread it around. Apply pressure until the glue sets.
Insert the objective lens when the first spacer is dry, with the second spacer against it. Apply glue to the hole, spread it and apply pressure until it sets.
Slide the inner tube into the outer tube, then focus the telescope by sliding the tube as necessary. Establish your desired focusing distance, and then attach the two ends permanently with glue or tape.
- You can obtain sonotubes from the lumberyard's concrete supplies section.
- Work slowly. Measure twice for every cut to make sure everything lines up.
- Brush dust off the optics with a fine camel's hair brush or blower. Clothes will scratch and dull lenses.
- Spend the bulk of your money on a big mirror, eyepiece lenses and big focuser that will take 1 ¼ inch or 2 inch eyepieces.
- Mount the cell and spider securely and center them. Good alignment is critical to a crisp image.
About the Author
Claire is a writer and editor with 18 years' experience. She writes about science and health for a range of digital publications, including Reader's Digest, HealthCentral, Vice and Zocdoc.