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How to Make a White Light Telescope

White light telescopes make viewing the sun safe. Observing the sun with a standard telescope or binoculars may cause blindness or permanent eye damage. White light filters, also called Solar Safety Filters, admit the entire spectrum of solar light but reduce it to only .001 percent of it's intensity to prevent eye injury. These filters are used to safely view solar phenomena such as sunspots, total eclipses and planetary transits. Both refractor and reflector telescopes can be converted to white light instruments simply by retrofitting with the appropriate filter. The most common white light filter is made of layers of Mylar film. Filters of metallic-coated glass are also commercially available in common telescope sizes. Another type, for refractor telescopes only, is the Herschel wedge filter that incorporates a prism and mounts in the optical path at the telescope eyepiece.

Things You'll Need

White light filter of either film, glass, or wedge variety.
Cardboard tube slightly larger in diameter than telescope lens hood
Scissors
White glue

Instructions

Installing Film Type White Light Filters
- 1
  Cut a circular piece of white light Mylar filter material to a size slightly larger than the lens hood at the end of the telescope. Cut a circular opening in two pieces of cardboard equivalent to the telescope's large lens aperture.
- 2
  Sandwich the Mylar film filter material between the two pieces of cardboard and glue together with white glue, taking care not to wrinkle nor stretch the filter.
- 3
  Cut a 2-inch-long piece of cardboard tube. Glue the film cardboard sandwich containing the film to one end of the tube segment. The white light filter cell unit can now be slipped in place over the lens hood at the end of the telescope.
Installing Glass Type White Light Filters
- 4
  Install the manufacturer-supplied adhesive felt strips inside the large end of the telescope, just before the lens.
- 5
  Mount the metal-framed white light filter against the felt strips that hold it in place.
- 6
  If an external-mount glass filter is used, slip the filter over the end of the telescope lens hood, and tighten the supplied knurled screws to secure.
Installing a Herschel Wedge Type White Light Filter
- 7
  Loosen the adjustment screw, and remove the existing standard eyepiece from the telescope focusing tube.
- 8
  Insert the Herschel wedge prism into the tube and rotate to the most convenient viewing angle.
- 9
  Tighten the adjustment screw to secure the wedge prism in the focusing tube.

Astronomy