DewBuster™ Controller
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The Ultimate Dew Controller
Precision temperature control keeps you dew free all night long while your telescope performs at its best. Easy to operate, stingy on power, built tough and reliable, and backed with a no-hassle 5 year warranty. Compatible with all major brands of heaters and 12VDC and 13.8VC power sources. Output configuration may be customized to your needs usually at no extra cost. Heavy Duty Power Cord with Powerpole® quick-disconnect accepts pigtails to accommodate most power sources.
Built To Last!
Designed for those who want the best and want it to last a long time. After almost 20 years of production 99% of all DewBuster™ Controllers are still in service! To prevent circuit board stresses and eventual cracked solder joints from plugging/unplugging heaters, RCA jacks are solidly mounted in quality powder-coated aluminum case. Heater outputs are short-protected to prevent damage from shorted heaters. I maintain purchase records so your receipt is not needed for the no-hassle 5-year warranty and I don't look for reasons to void your warranty which even covers damage from home-made or shorted heaters. And even after the warranty period expires your DewBuster™ Controller is repairable at a very modest cost!
Quit wasting time fiddling with your dew controller when you should be using your telescope. Color-coded outputs make connections easy and the night-vision friendly red LED's blink to assure you it's working properly. No confusing controls to struggle with in the dark, simply turn one knob and forget about dew. No cryptic programming sequence to figure out and no need to recalibrate the controller when switching temperature sensors.
Temperature Controlled!
Temperature Sensor measures both air and telescope temperatures and DewBuster™ Controller automatically controls heater temperature slightly above air, preventing dew while maximizing telescope performance. Swapping temperature sensors has no affect on calibration so no need to remember which sensor goes with which channel.  This also means you can order extra sensors for each of your telescopes and move the controller back and forth while never needing to recalibrate. Ambient Air Sensors are located in sensor cables to prevent errors if controller is mounted on a warmer or colder surface. When used without a sensor, that channel switches to Medium Power so the output is not wasted.
Stingy on power!
Temperature control saves battery energy early in the night when telescope is cooling-down, then applies only what's needed to keep telescope from cooling below air temperature. Synchronized Pulse Width Modulation (PWM) is efficient and reduces peak current by alternating voltage pulses between the Temperature Controlled and Medium Power outputs to reduce battery voltage fluctuations. Low Battery circuitry doesn't just shut off heaters, it gradually reduces power to heaters keeping your optics dew-free as long as possible while giving you time to switch power sources or unplug less important items to conserve energy. And it will not allow your battery to run below the 10.5V minimum recommended by most battery manufacturers.
No Risk 30-Day Satisfaction Guarantee
If you are not completely satisfied with your DewBuster™ Controller for any reason you may return it for a full refund minus shipping.
Order Form

  • 10 Output Jacks -- Heater Output Jacks are mounted to aluminum enclosure, not the circuit board. This prevents cracked solder joints from stresses of plugging and unplugging heaters. Standard SCT/Refractor configuration shown above has two Temp Controlled outputs (one on each side), six Medium Power outputs, and two 12V Power Outlets.
  • Temperature Controlled Outputs -- When a Temperature Sensor is plugged in, the Temp Controlled Output constantly adjusts heater power level to keep the lens just a few degrees F above the air temperature (as set by control knob). This insures optimum telescope performance and maximum energy savings so your battery lasts longer. On very large heaters the energy savings can be significant. If a Temperature Sensor is not plugged in, that Temp Controlled output operates at Medium Power so the output is not wasted.
  • Medium Power Outputs -- does not use a sensor but instead applies extra power to insure dew does not form. Typically used for small non-critical heaters such as eyepiece, finder scope, Telrad, etc. where the extra heat will not affect telescope performance and there would be very little energy savings.
  • 12V Power Outlets -- provide constant 12V power for accessories such as Digital Setting Circles or Cameras. These outlets are not regulated, they pass through power from the battery and will remain powered even when the DewBuster™ Controller is turned off.
  • Heavy Duty Powerpole® Power Cord -- quickly and easily switch between "pigtails" connected to different power sources. Self-resetting 16 Amp PTC fuse means no fuses to replace. Wide choice of pigtails to fit most power sources. Default length is 8 feet but may be customized if needed.
  • Short Circuit Protected Heater Outputs -- Heater outputs are short-circuit protected so heater faults can't damage controller.
  • Synchronized Pulse Width Modulation -- For maximum efficiency Pulse Width Modulation (PWM) is used to control power to your heaters, but the DewBuster™ Controller takes it to the next level by alternating pulses between Temperature Controlled and Medium Power outputs to reduce peak current and thus fluctuations in battery voltage.
  • Customize Your Controller -- Every DewBuster™ Controller is hand built allowing me to customize it to best suit your needs. If you need assistance do not hesitate to contact me. With a DewBuster™ Controller you are never stuck, if you ever wish to reconfigure your controller outputs or power cord then you can send it in for an upgrade and in most cases you will only pay return shipping plus the cost of the options being added.
  • Proven Technology -- Industrial-Spec components for dependable performance 24/7 even in extremely cold weather.
  • Longevity -- In production for almost 20 years and 99% of all DewBuster™ Controllers built are still in service!
  • No Camera Interference -- The DewBuster™ Controller will not interfere with Camera equipment and the 30-Day Satisfaction Guarantee allows you to return it if you are not completely satisfied.
  • Heater Status Lights -- LED's are wired directly to heater outputs so if they are illuminating then you can be sure voltage pulses are being sent to your heaters. When the Temperature Controlled LED blinks you know that the temperature is being maintained at the control knob setting. Red LED's are easily visible at night yet dim enough not to disturb your night vision.
  • Battery Status Light -- Yellow Battery warning light flickers dimly when battery is weak to give you time to switch power sources or disconnect less critical heaters or accessories. As battery weakens further the blink grows longer and brighter giving you a visual cue as to how fast your battery is draining.
  • Smart Low-Battery Circuitry -- As battery nears 10.5V the heater power levels are reduced gradually to provide as much heat as possible while never allowing the battery to fall below 10.5V. This allows your heaters to run as long as possible while preventing battery damage.
  • Premium Enclosure -- No plastic or thin metal, the deluxe cast aluminum enclosure is finished in durable polyester powder coat. Durable and scratch-resistant Lexan® front panel graphics. Enclosure measures a compact 4.4" x 2.4" x 1.2".
  • Easy Mounting -- Included industrial-strength Velcro® strip holds tight but allows easy removal when breaking down scope. For those desiring a more permanent mounting, the 6-32 bottom cover screws may be replaced by longer screws to allow mounting to a plate or bracket.
  • Prevents overheating optics- Keeps optics slightly warmer than the air temperature, just enough to prevent dew but won't hurt telescope performance.
  • Set & Forget - Just set the control knob at the beginning of the night and thermostatic controller does the rest. In an observatory the controller may be left on 24/7 to help with daytime condensation.
  • Sensors do not require calibration - No need to remember which sensor goes with which channel and you can purchase extra sensors for a second telescope and move the controller back and forth with no fuss.
  • No drift in accuracy as temperature changes -- The DewBuster™ Controller uses dependable thermocouple technology which does not drift over wide temperature extremes allowing accurate and precise temperature differential control.
  • Interchangeable low cost Temperature Sensor Cables - Air and telescope temperature sensors are combined into one Temperature Sensor Cable to minimize extra wires. Two Temperature Sensor Cables may be used simultaneously which allows temperature control of 2 optics. There is seldom a need for more since Medium Power is used for smaller items such as the finderscope, eyepiece, Telrad, etc. If you have more than one telescope the sensors are easy to move between telescopes, however you may equip each telescope with sensors since calibration is not affected by swapping sensors.
  • Sensor is easy to install - SCT/Refractor type sensor clips on heater strip. The six foot long cable matches the cord length of most heater strips (you may request a shorter length). For applications where a standard heater strip is not being used, a special Newtonian type Temperature Sensor Cable is available where the tip is glued in place (CLICK HERE for more information on the Newtonian Sensor installation).
  • The DewBuster™ Controller does not include heater strips but is compatible with most commercial 12V heaters as well as heaters built using my instructions. You may use a mixture of home-made and commercial heaters.
  • The DewBuster™ Controller has short-circuit protection so heater faults will not damage it and the warranty even covers damage caused by improperly constructed home-made heater strips.
  • Conserves Battery Power - Temperature control applies only as much heat as needed to replace what is being lost to the sky. You can save energy by wrapping insulation around the outside of a temperature controlled heater which will reduce heat losses and the controller will automatically reduce power to the heater resulting in longer battery life.
  • Efficient - Pulse Width Modulated heater output circuitry with Power MOSFET drivers for maximum efficiency and longer battery run time.
  • Low Battery Light - yellow light flickers when battery gets below 11 VDC then brightens as battery weakens and remains on constantly when battery is exhausted.
  • Smart Low-Battery Circuitry - reduces heater power as battery becomes exhausted keeping dew heaters operational as long as possible yet preventing battery damage. Works in conjunction with Low Battery warning light so you can disconnect unnecessary items to conserve power. Provides peace of mind if you leave controller turned on when going to bed.
  • 30-Day Satisfaction Guarantee - If you are not satisfied with your DewBuster™ Controller for any reason contact me for return instructions. You will be given a full refund minus shipping.
  • No-Hassle 5-Year Warranty - Your DewBuster™ Controller is warranted to the original purchaser for a minimum of 5 years against failures of any kind including reverse power hookup and damage caused by shorted heaters of any brand including home-built heaters. I keep a record of your purchase so your receipt is not needed for warranty service. After the warranty expires, repairs will be done for a very reasonable flat-rate fee.
  • DewBuster™ Controller
  • Velcro™ mounting strip
  • Owner's Manual
Heaters strips and power source not included.

NOTE: The order form defaults to one Temperature Sensor Cable which is what most users will need. You may add or delete sensors to match your needs, but keep in mind that only two sensors can be used at one time. See instruction manual for more information.
  • DewBuster™ Controllers are sold only through this web site, not through dealers.
  • Prices, options, and shipping are shown on the ORDER FORM below.
  • If you need help configuring your controller, fill out the order form as best you can and hold off making your payment. Reply to the confirmation email with your questions and I will assist you in configuring your controller and adjust your order as necessary. After we finalize your order you can make your payment if you wish to proceed.
  • International orders are welcome!

Links for other order forms:        Newtonian DewBuster       Accessories      Fan Speed Controller
Standard DewBuster™ Controller Order Form
This form DOES NOT collect any payment, when you SUBMIT ORDER you will be emailed an order summary with a link to make your payment. You can reply to the email with questions and I will send you a personal reply. You may request changes to your order right up until the time it ships and I can adjust your order so you will only have to fill this form out one time. Your information is kept completely confidential, it will never be shared with any other parties.
ACKNOWLEDGEMENT: DewBuster™ Controllers are built-to-order which takes about a month.
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DewBuster™ Controller:

I recommend Powerpole® Heavy Duty Power Cord (requires pigtail to connect to your power source).

TEMPERATURE SENSORS: Two sensors maximum may be used simultaneously. See FAQ for help deciding which optics to use sensors on.

Standard SCT/Refractor Temperature Sensor Cable (clips to heater strip):

Newtonian Temperature Sensor Cable (for Secondary Mirror. See Installation Instructions):
Output Configuration (CLICK HERE FOR HELP):

RCA Plug to Screw-Terminal Adapters (use to connect +12V Outputs to your wiring):
RCA to SCrew Terminal Adapaters Click for more information

Resistors (330-Ohm, 1/2W) for building home-made heaters:

Priority Mail Shipping & Handling (does not include duties):

Telescope Type/Aperture:

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