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Why do I need a DewBuster™ controller... my current dew heater does a fine job of keeping dew off? Your dew prevention system needs to prevent dew WITHOUT hindering your telescope's performance. The reason you bought a telescope was to view highly magnified images of objects in the night sky which requires your optics to cool down as close to the air temperature as possible. It makes no sense to purchase excellent optics and then cripple the telescope's performance by blindly applying heat to the lens.
Common anti-dewing systems do not control the temperature of the telescope, they only control how much heat energy is being applied to the telescope leaving you to guess how much heat to apply. The temperature of your optics will vary through the night and be dependent on many variables such as wind, sky transparency (affects radiation cooling), how fast the night air temperature is dropping, length and insulating qualities of dew shield, and many other factors.
Your primary concern becomes preventing dew, so human nature takes over and you end up increasing the heat setting until the heaters "feel" warm. While this will prevent dew, it hurts telescope performance. Your telescope performs at its best when the corrector plate (or objective) is at the same temperature as the outside air. Too much heat will deteriorate the telescope images and you will mistakenly blame it on poor seeing conditions.
The DewBuster™ controller does what humans can't, it compares the outside air temperature to the telescope temperature and constantly adjusts the heater power level to keep the corrector plate just slightly warmer than the outside air. Since the DewBuster™ controller is not really heating the telescope, just keeping it from getting cold, it will not cause tube currents. In fact, placing your hand on the telescope, it may actually feel colder than the air even though this is not the case.
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The DewBuster™ controller is a high-quality thoroughly-tested product with many satisfied owners. The DewBuster™ controller delivers where it counts with precision heater control and dependability. The heater outputs are short circuit protected so that a shorted heater strip will not damaged the controller. It uses the proven technology of industrial-spec linear integrated circuits for dependable performance even in extreme cold weather operation. In both heat of summer and cold of winter, the DewBuster™ controller will keep your telescope at the set temperature differential performing its best without risk of dew. The controller is built to last and may be run in an observatory environment 24 hours every day to help keep the telescope condensation free.
The DewBuster™ controller is housed in a compact 4.4" x 2.4" x 1.2" premium quality aluminum enclosure with tough polyester powder-coat paint for a lasting finish. Attractive front panel graphics are durable scratch-resistant Lexan®. The standard 6 foot power cord's heavy-duty cigarette plug is rated for 10 Amps (comes with a 5 amp fuse but up to a 10 amp fuse may be used if your cigarette socket can handle the current). For large telescopes or permanent installations the optional ring-terminal power cord is recommended.
The DewBuster™ controller measures the telescope temperature and constantly adjusts the AUTO heater power level to maintain the corrector plate (or objective lens) slightly warmer than the air temperature. The control knob matches the temperature to your telescope's needs (lowest setting that never allows dew to form). Once the optimal temperature for your telescope is found, just set it there at the start of each observing session and forget about it. Only one AUTO output jack is normally used (corrector plate or objective) but 3 AUTO jacks are provided for special situations such as large telescopes with double heater strips or a guidescope objective
5 AUX outputs provide plenty of expansion room for auxiliary heaters such as the finder scope, finder eyepiece, telescope eyepieces, star diagonal, Telrad, camera lens, hand controller, etc. Temperature control is not needed on these heaters since they do not affect telescope performance and use much less power. The AUX outputs normally run at 40% power but will go to 100% when the AUTO temperature sensor detects the telescope is warming up.
If desired, your DewBuster™ controller may be ordered with any of the heater outputs wired as 12V power (always on). If you would like a custom configuration please contact me prior to ordering to clarify how you would like it configured or for recommendations.
To protect your night vision the DewBuster™ controller has red LED's on both the AUTO and AUX outputs. The LED's turn on and off as the heaters receive pulses of power. The blinking of the LED provides indication of the power level, the faster it blinks the more power the heater is receiving.
The smart low battery circuitry senses when your battery's charge is low and reduces heater power levels to balance battery protection with keeping the heaters in operation as long as possible. The Low Battery light is yellow to capture your attention but is dim enough not to interfere with your night vision. The light is normally off and blinks when battery voltage is low. The blink duration increases as battery weakens so you can monitor battery condition and disconnect unneeded loads to extend run time. The light stays on when battery is exhausted (10.5V under no-load condition) and heaters shut off (red lights are off) to prevent damaging your battery.
The DewBuster™ controller is supplied with one dual temperature sensor cable that measures both telescope and outside air temperature. If you have several telescopes, the sensor can easily be moved from one scope to another. Additional sensors may be purchased separately if you wish to leave a sensor attached to each of your telescopes, but only one sensor cable can be plugged into the DewBuster™ controller at a time. The standard SCT/Refractor Type sensor is shown above, but a Newtonian Sensor is available (select appropriate box on order form).
The DewBuster™ controller does not come with heating elements. It is fully compatible with commonly available heating elements such as AstroZap, Dew-Not, Kendrick, Telescope Solutions, or Thousand Oaks. Many people like to build their own heating elements and save money in the process. A popular choice is to purchase a commercial heater for the corrector plate and build the smaller heater strips such as eyepiece, finder, etc.
The DewBuster™ controller is warranted to the original owner for two years.
You may also wish to visit Excelsis telescope ratings web site, an uncensored independent forum where owners have posted opinions about their DewBuster™ controller and other astro products.
Please e-mail me if you have any questions.
