Adapting a Flashlight for Astronomy

Night vision is key to astronomy. On moonless nights when galaxies, nebulae or globular clusters are at the top of your observing list, properly adapted eyes can be as important as the aperture of the telescope for spotting a “faint fuzzy”. The June and July editions of Sky & Telescope each have articles detailing how to adapt a flashlight for astronomy. Inspired by these articles, I decided it was time to put together my own red flashlight. Since red light is more forgiving to the eye when it is dark-adapted, this is the preferred way to light up an area while still keeping most of your night vision. While red flashlights can be found from companies such as Celestron and Orion for fifteen to thirty dollars, I didn’t care much for their designs and decided to build my own.

Step 1:
After a trip to Target and Advanced Auto Parts,
I had an LED Flashlight and Red Tail Light Repair Tape.IMG_8936

Step 2:
Cutting out a small piece of the red tape, I placed it over the light.

Step 3:
Using a pair of scissors and a sharp knife from “Cutlery Corner”, I trimmed the tape and carefully cut it down to size, only covering the lens.

After using the flashlight to set up and organize equipment, I realized the beam was a bit more pink than red, so I added another layer of tape which turned it into more of a solid red beam. While the brightness, at 37 lumens, is slightly more than is recommended, I’m not too concerned about it because I already am contesting with neighborhood light pollution which will hurt my night vision long before this red flashlight will. For only about fifteen dollars, I now have a stylish LED red flashlight that will hopefully keep my night vision a little more intact on those nights of deep sky observing.


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