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 - Standard configuration shown above has 2 Temperature-Controlled outputs (one Left, one Right), 6 Medium Power outputs, and 2 pass-through 12V Power Outlets.
  • Case-Mounted Output Jacks - plugging and unplugging heaters won't stress the circuit board and crack solder joints.
  • Temperature Controlled Outputs - When used with Temperature Sensor, constantly adjusts heater power level to keep the lens just a few degrees F above the air temperature (as set by control knob). This prevents dew formation while ensuring optimal 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, the Temp Controlled output functions as a Medium Power output.
  • Medium Power Outputs - instead of using a sensor to measure temperature, Medium Power outputs apply 40% power which is sufficient to prevent dew but will usually warm the optic more than needed. Typically used for small non-critical heaters such as eyepiece, finder scope, Telrad, etc. where the extra heat will not affect telescope performance and the energy savings is not significant. Medium Power outputs will gradually increase from 40% to 100% when control knob is raised above 15.
  • Pass-Through 12V Power Outlets - provide power for accessories such as Digital Setting Circles. These outlets are not voltage-regulated, they pass-through power from the battery and thus remain powered even when the DewBuster™ Controller is turned off or the Low-Battery or High-Voltage Cutout features activate.
  • 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.
  • 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. Yellow light also functions as a High Voltage warning and will illuminate when voltage exceeds 16V.
  • 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. Please note that the red 12V power outputs are pass-through and thus are not shut off by the Low-Battery Circuitry.
  • High-Voltage Cutoff - If your power supply malfunctions and voltage exceeds 16V, the DewBuster™ Controller shuts off all heaters to prevent them from being damaged. Please note that the red 12V power outputs are pass-through and thus can not be shut off by the High-Voltage Cutoff feature.
  • Premium Enclosure - No plastic or thin metal, deluxe cast-aluminum enclosure finished in durable polyester powder coat with durable 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 yet allows easy removal when breaking down equipment. For those desiring a more permanent mounting, the bottom cover screws may be replaced by longer 6-32 screws to allow mounting the DewBuster™ Controller to a plate or bracket.
  • Customize Your Controller - I hand-build every DewBuster™ Controller to order which allows me the flexibility to customize it for your needs. Do not hesitate to contact me to discuss your needs.
  • After-Sale Support - With a DewBuster™ Controller you are never stuck if your needs change. If you ever wish to reconfigure your controller outputs or power cord then contact me. In most cases you will only pay return shipping plus the cost of the options being added.
  • Set & Forget - Just set the control knob at the beginning of the night and thermostatic controller does the rest. Controller may be left on 24/7 to help with daytime condensation in an observatory.
  • No overheating optics - Keeps optics slightly warmer than the air temperature, just enough to prevent dew without hurting telescope performance.
  • Combination Sensor - both air and telescope temperatures combined into one cable to reduce clutter.
  • 2 Sensor Cable Inputs - two Sensor Cable inputs allow independent control of your main optic and a piggybacked telescope. Note that smaller items such as finderscope, eyepiece, Telrad, etc. do not require precise temperature control and are best used on the Medium Power outputs.
  • Zero-Drift Sensors - dependable thermocouple technology does not drift over wide temperature extremes providing precise temperature control even on the coldest nights.
  • No-Calibration Sensors - sensors cables do not affect calibration so controller(s) and sensor(s) may be interchanged between multiple telescopes without affecting accuracy.
  • Clip-On Sensor - standard Refractor/SCT Sensor Cable clips onto heater strip so it is  easy to move between telescopes.
  • 6-foot Sensor Cable - cable length matches cord length of most heater strips.
  • Newtonian Sensor Available - For applications that don't use standard heater strips, a special Newtonian Temperature Sensor Cable is available. It has a smaller "tip" sensor that can be glued or taped in place. For more information on Newtonian Sensor installation CLICK HERE.
  • Low Cost Sensors - extra sensors may be purchased at any time and are economically priced.
  • Sensor Customization - for special situations such as needing the cable shorter than 6 feet, just contact me with the specifics. There is no extra charge for shortening dimensions, but when lengthening there will be an extra charge if additional materials are required.
PLEASE NOTE: Heater strips are not included with controller.
  • Commercial Heaters - compatible with RCA-plug equipped 12V heaters such as those listed here.
  • Home-Made Heaters - you can build heaters using my resistor heater or nichrome heater instructions and they will be fully compatible with commercial heaters allowing you to mix and match. For example, you could buy the corrector plate heater and build eyepiece and finderscope heaters. Note that instructions from other sources may be used, but if they do not produce the correct wattage you will have excessive heat or dew-up.
  • Short Protection - shorted heaters can not damaged the controller.
  • Un-Equaled Warranty - you can build your own heaters without worry because the warranty covers damage caused by any mistakes you make constructing 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 - warranted to original purchaser for a minimum of 5 years against failures of any kind including reverse power hookup and damage caused by faulty heaters including home-made. 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 only two sensors can be used at one time (allows controlling 2 optics). See instruction manual for more information.
  • DewBuster™ Controllers are sold only through this web site.
  • 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.
  • I ONLY SHIP TO USA OR APO ADDRESSES, I do not ship international but international customers are welcome to ship to a "Package Forwarding Service"  in the USA.

Standard DewBuster™ Controller Order Form
This form emails you a quote with instructions to place the order. You are under no obligation and may reply to the email with questions or request changes. Your information is kept confidential and will never be shared with any other parties.
DewBuster™ Controllers are built-to-order which takes time, typically about a month but I currently have a very large backorder so it may take longer. You may cancel at any time if you are unable to wait.
Acknowledgement: Type yes to acknowledge.

DewBuster™ Controller:
Output Configuration:
CLICK HERE if you need help selecting an output configuration.
I recommend Powerpole® Heavy Duty Power Cord (requires pigtail to connect to your power source).
Power Cord:
Powerpole® Pigtails for use with Powerpole® power cord above. CLICK HERE for more info

Temperature Sensors:
The DewBuster™ Controller you selected above does not include Temperature Sensors, they are selected below. Note that a maximum 2 Sensor Cables may be used simultaneously. See FAQ for more information.
SCT/Refractor Temperature Sensor: (clips to heater strip)
Newtonian Temperature Sensor: (for Secondary Mirror)
For Newtonian Sensor, see Installation Instructions and email me the 'A' dimension.

RCA to SCrew Terminal Adapaters
Used to connect your wiring to +12V Outputs. CLICK HERE for more information.
RCA to Screw-Terminal Adapters:
Used to build heaters using my home-made heater instructions.

100 Pack of 330-Ohm 1/2W Resistors:

Telescope Type/Aperture:
Shipping & Handling:


Sorry but I ONLY SHIP TO USA OR APO ADDRESSES. International customers may ship to a Package Forwarding Service in the USA who can then reship to you.
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Country: United States
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