A Do-It-Yourself

Dew Heater

for an SCT

Tools and Materials


Here's what you'll need to build it. Altogether it should set you back less than US$50 (not counting all the extra stuff you buy because you think you might need it someday):

4 ft3/8" thick, 1/2" wide foam weather stripping (you need just enough to go around the edge of your corrector plate; for the 12" LX200 its really 41 inches)
~100 ftthin insulated wire (AWG 30); 4 colors (I used wrapping wire)
165 ohm 1/4 watt resistors
13610 ohm 1/4 watt resistors
51k ohm 1/4 watt resistors
52k ohm 1/4 watt resistors
5LED holders
4small SPST toggle switches
1small SPDT center-off toggle switch
13 amp fast-acting fuse
1inline fuse holder
1small project box
 electrical tape
~10 ft2 conductor insulated wire (approx. AWG 12)
2coaxial DC plugs (male)
1coaxial DC jack (female)
 double sided sticky foam tape
 glue (any kind that will stick to the foam will do; I used black aquarium cement)


  • long-nosed pliers
  • wire cutters or strippers
  • soldering iron & solder
  • magnifying glass (for those with old tired eyes)
  • drill
  • measuring tape
  • multimeter
  • Swiss Army knife (you always need a Swiss Army knife)

Main page . . . Theory . . . Construction
Bill Arnett; last updated: 1996 September 17 ; suggestions or corrections appreciated