DewBuster

DewBuster™ Precision Thermostatic Dew-Heater Controller
The "Set & Forget" Dew Controller

*Built To Last!* Designed for those who want the best and want it to last a lifetime. Case-mounted RCA jacks won't stress circuit board. Outputs are short circuit protected so heater faults can't damage controller. No-hassle 2-year warranty even covers damage caused by home-made heaters. And don't worry about where you put that receipt because I'll keep a record of your purchase so you don't have to. After the warranty your investment is safe because the controller is fully repairable at a very modest cost, a DewBuster™ Controller exclusive in today's world of throw-away electronics.
*Uncomplicated!* Quit wasting time with your dew controller and start using your telescope! No confusing controls to struggle with in the dark, simply turn one knob and the blinking lights tell you it's working. No programming required and no need to recalibrate when changing temperature sensors.
Temperature Controlled! Two independent Temperature Control channels allow using 2 Sensor Cables to independently control heaters and keep two different optics just above air temperature to prevent dew while maximizing telescope performance. And no recalibration is required when swapping temperature sensors, a DewBuster™ Controller exclusive!
Stingy on power! Reduces heat during telescope cool-down, then applies just enough heat to prevent telescope from cooling below air temperature. Synchronized Pulse Width Modulation circuitry alternates pulses between Temperature Controlled and Medium Power outputs reducing maximum instantaneous current and keeping battery voltage more stable. Also features low battery circuitry which detects when battery reaches exhaustion and reduces heat gradually to prevent dew as long as possible while preventing battery damage.
*No Risk 30-Day Satisfaction Guarantee* If you are not satisfied with your DewBuster™ Controller for any reason you may return it for a full refund minus shipping.

Excelsis - an independent ratings web site where DewBuster™ Controller owners have rated their controllers.

10 Output Jacks -- Standard configuration is shown above. Up to 10 Amps total current available with standard Cigarette Plug model (HD Power Cord models available with additional current capability). Outputs are short-circuit protected so heater faults can not damage controller. Temperature Controlled Outputs are typically used for corrector plate, objective, or guide scope heater. If no Temperature Sensor Cable is plugged in then the associated jacks will function as Medium Power Outputs. Medium Power Outputs are not temperature controlled and are typically used for accessory heaters such as eyepiece, finder scope, Telrad, etc. The Power Outlets provide power for accessories that run on 12VDC and remain powered even when the DewBuster™ Controller is turned off.
Synchronized Pulse Width Modulation Circuitry -- Alternates pulses between Temperature Controlled and Medium Power outputs. On the typical large Schmidt-Cassegrain telescope the corrector plate heater consumes about half the total heater current. By alternating on-off pulses between the Temperature Controlled heater (corrector plate) and the Medium Power heaters (finder, eyepieces, etc.) they are not on simultaneously which results in lower maximum current at any one instant. Lower instantaneous current means higher battery voltage with less fluctuations.
Customize Your Controller -- You may customize the output jack configuration to better suit your needs. You may also select from a variety of Power Cord Options. Since every DewBuster™ Controller is hand built, not mass produced, I can customize it to best suit your needs. If you need help customizing, contact me and I will be happy to offer assistance. Your satisfaction is my #1 goal. With a DewBuster™ Controller you are never stuck, if you later 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. This even applies after the warranty has expired!
Proven Technology -- Industrial-Spec components for dependable performance 24/7 and cold weather operation down to at least -40F.
Mature Product -- Thousands of units in service with extremely satisfied users and reliability second to none.
No CCD Interference -- The DewBuster™ Controller will not interfere with CCD equipment.
Heater Status Lights -- Temperature Controlled and Medium Power LED's are wired directly to heater outputs and illuminate as voltage pulses are sent to heater so you know the heaters are getting power. When Temperature Controlled light blinks you know temperature is being maintained. Lights are red and dim enough not to interfere with your night vision.
Battery Status Light -- Yellow Battery warning light flickers when battery is almost exhausted, then smart Low-Battery Circuitry reduces heater power levels gradually to prevent dew as long as possible while preventing battery from falling below 10.5V to prevent battery damage.
Power Cord -- Standard cigarette plug power cord is 10-feet long and fused at 10 Amps. For observatory installations or large telescopes a Heavy Duty Power Cord is available with many terminal choices and features a self-resetting PST fuse.
Premium Enclosure -- deluxe 4.4" x 2.4" x 1.2" cast aluminum enclosure with durable polyester powder coat finish. Durable and scratch-resistant Lexan® front panel graphics.
Easy Removal -- industrial strength Velcro™ strip included to hold tight but allow easy removal when breaking down scope.

Prevents overheating optics - Keeps optics slightly warmer than the air temperature, just enough to prevent dew but not so much that it prevents your telescope from performing at its best.
Set-&-Forget thermostat control - Just set the control knob at the beginning of the night and controller does the rest. In an observatory the controller may be left on 24/7 to help with daytime condensation.
No recalibration when changing temperature sensors -- The DewBuster™ Controller is unique in that it does not have to be recalibrated when changing temperature sensors, a very important consideration if you want to have a sensor on each of your telescopes.
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 control.
Interchangeable low cost temperature sensors - The controller comes with one sensor but there are two sensor input jacks so a second sensor may purchased for use with a piggybacked scope. You may also wish to purchase extra sensors if you have several telescopes. The DewBuster™ Controller does not require recalibration when swapping sensors, a major advantage over competitors.
Differential Temperature Sensor - air and telescope temperature sensors are combined into one cable to minimize extra wires. Telescope sensor conveniently clips under heater strip and can easily be moved between telescopes. Six foot long cable matches the cord length of most heater strips. The Standard Sensor clips onto your heater strip for easy installation. For applications where a heater strip is not being used, an special Newtonian Sensor is available and the tip may be attached to the mirror with epoxy or other means (CLICK HERE for more information on Newtonian Sensor).

The DewBuster™ Controller does not come with heater strips. You may use commercial 12V heater strips or have fun and save money by building home-made heater strips. The DewBuster™ Controller has short-circuit protection so you never need to worry about heater faults damaging your controller and if something does happen your warranty covers any damage caused by your mistakes building home-made heater strips. You'll have the flexibility to use any combination of home-made or mixing brands of heater strips without worrying about your warranty.

Conserves Battery Power - applies only as much heat as is needed to replace what is being lost to the sky. If insulation is wrapped around outside of heater, the controller reduces heater power which translates into longer battery run times.
Efficient - Pulse Width Modulated heater output circuitry with Power MOSFET drivers for maximum efficiency and longer battery run time.
Low Battery Light - yellow light provides advanced warning of discharged battery. Light is normally off and when battery is discharged it begins to flicker dimly. Light brightens as battery weakens allowing you to monitor battery condition and disconnect unneeded loads (less battery load will cause the yellow light to dim since run time has been extended). When battery is exhausted the yellow light will remain on solid but the Temperature Controlled and Medium Power heater lights will be off since the heaters are shut down.
Smart Low-Battery Circuitry - senses low battery voltage and gradually reduces heater power to keep dew heaters operational as long as possible. Allows heaters to run as long as possible but will not allow damage to your battery. Provides peace of mind at a star party if you forget to turn it off 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 2-Year Warranty -- Your DewBuster™ Controller is warranted to the original purchaser for a minimum of 2 years against failures of any kind including reverse power hookup and damage caused by shorted heaters regardless of brand or whether home-built. Failures beyond the 2 year period will be evaluated and in many cases repaired under good will. Repairs not covered under warranty or good will will be repaired for a very reasonable flat-rate fee. CLICK HERE for more information.

DewBuster™ Controllers are not sold through dealers, they are available only through this web site. They are not mass produced either, each controller is custom built so you can configure it to best meet your needs. Do not hesitate to contact me for recommendations or assistance. Filling out the order form is just step one, you will have the option of contacting me for advice and I can adjust your order before you submit your payment.

This is a special version of the DewBuster™ Controller tailored to the needs of the large Dobsonian telescope. It was developed in collaboration with Markless Astronomics to give the Big Dob owner the benefits of a dew controller with a built-in power distribution rail for powering accessories on the upper cage. Markless Astronomics has developed a mounting bracket, power cables, and DewGuard wiring kits to make the installation of the Big-Dob DewBuster™ Controller a simple plug and play installation. Contact Charlie Starks of Markless Astronomics for information and assistance with the mounting bracket and wiring for installation of the controller on your telescope. The Big-Dob DewBuster™ Controller may be ordered using the order form on this web site and do not hesitate to contact me if you have any questions about the controller or options available on the order form.

The main difference between the Big-Dob and the standard controller is that it is powered through an RCA jack on the bottom rather than using a power cord. In addition the Temperature Sensor Cable has been made optional to save you $20 since many big Dob users will not use the Temperature Sensor. The controller has all circuitry needed for Temperature Control so the Temperature Sensor(s) may be added to your order (under options) or purchased later (using Accessories Order Form). A self-resetting PST fuse is used on the RCA Power Input so the Accessory Power Outlets are protected but may provide up to 10 Amps of current (combined current of all 12V accessories and heaters is limited to 10 Amps by the PST fuse). An optional Cigarette Plug Power Cord is available to plug into the RCA Power Input jack and allow the controller to be used on a second telescope such as your Grab&Go scope. The price of the "Big Dob" DewBuster™ Controller is $150 and the optional Temperature Sensor Cables are $20 each.

Item	Description	Price
Ring Terminals on Power Cord	Eliminates the Cigarette Plug. Recommended for large telescopes because it provides excellent low-resistance connections for better current flow and higher voltage at the heater strips. Comes in 1/4", 5/16", 3/8" ID stud sizes . Before ordering CLICK HERE FOR IMPORTANT INFORMATION.	$10
Extra Dual Temperature Sensor Cable	One Temperature Sensor Cable is supplied with the DewBuster™ Controller. However the controller can accept 2 sensors, so if you have a piggybacked scope you may wish to purchase an additional Temperature Sensor Cable. You may also wish to have a spare or want to keep one with each telescope. If you already have a DewBuster™ Controller then CLICK HERE to order only the Temperature Sensor Cable.	$20
Resistors for building heaters	330 ohm, 1/2 watt, 5% tolerance, pack of 100. Used for for building dew heaters. If you want to order just resistors then CLICK HERE.	$5