How to make red flashlights

Here's a picture of a red LED flashlight you can make to use when observing.

Its' deep red light and ability to dim keeps it from ruining your night vision. This was taken from Sky & Telescope's home page. The numbers are Radio Shack part numbers. Wire the longer LED lead to the positive (+) side of the battery holder. If you want a more diffuse light, use sandpaper or steel wool to roughen the front of the LED.

If you're handy, you can make a red LED light by 'hollowing out' a flashlight bulb (remove the glass bulb, wires, and glue from the metal base), and soldier in a bright LED and a 47 ohm resistor.

The resistor is needed to limit the current to a level that won't damage the LED. The assembly is put in any standard two cell flashlight (ones that use AA size batteries are handy). The current drawn by the LED and resistor is much less than a normal bulb, so your batteries will last practically forever.

Annother way to make a red observing light is to take a regular flashlight, remove the lens, and use the lens to trace a circle on a piece of red paper. Cut out this circle and reassemble the flashlight with the disk of red paper between the reflector and the lens. The light given off by this light is not as spectrally pure as the LED light, but it will be more diffuse. Some people like this diffuse light better than the bright spot thrown by the LED light. Try both and see which one you like better.

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