Dew Removers

Astro-Physics has carried the Kendrick Dew Removal System for many years. Jim Kendrick innovated the concept of dew removal systems in the mid-1990's to meet a persistent need in the burgeoning astronomical community for effective dew removal and prevention. His system quickly became the benchmark for dew prevention. Over the years, he has continued to innovate with new features and functions to meet the needs of our time.

Repeated field testing on many types of optical systems under many conditions and hundreds of satisfied customers has proven the effectiveness of this product over and over. It also has these other attractive features:

  • Energy efficiency - Variable settings on the controller allow maximum conservation of battery power.
  • Heat range adjustable.
  • Lightweight.
  • High quality manufacture.
  • Versatility - Capable of keeping every optical surface moisture-free during an observing or astrophotography session.
  • Guaranteed to be effective thus extending your observing time on dewy evenings.
  • Radio frequency interference free.

Kendrick DigiFire FX and FX-Pro Controllers

These full-featured controllers were introduced in January 2019 and represent the culmination of years of R&D. Be sure to check out the features and functions within the product descriptions.

Kendrick Premier Heaters

The Premier Heater line is Kendrick's flagship brand and their highest quality heater. They use the best quality Velcro, elastic and flex heaters and are custom built to their electrical specifications. The cables are cold flexible down to temperatures of -40 and the cable housing is custom make for Kendrick to their specifications.

Kendrick heaters have been built to use only as much power as necessary and thereby not waste energy. The built-in foam insulation on one side to helps to prevent heat loss in the atmosphere and direct the warmth generated by the heaters into the optics.

Kendrick Premier Heaters must be used with Kendrick Dew Controllers. We offer a range of heaters for your telescope optics, eyepieces, finders, guidescopes and binoculars.

Amp Hour Ratings and Fitting Dimensions

Please bear in mind that the following table of amp hour ratings is to be considered accurate only if the controller is set at high. Under normal operating, conditions these ratings can be reduced by 40% to 60% as the normal controller setting is medium to low. This table will also help you determine which heater is right for your scope.

Our Part # Heater Size AP Scope Product Description Amp Hour Rating
KDRTEL Telrad   for Telrad .4
KDR965 .965"   for .965" eyepieces and finder scope eyepieces .2
KDR125 1.25"   for 1.25" eyepieces .2
KDR002 2"   for 2" eyepieces, 50mm finder scope objectives, and some camera lenses .3
KDR003 3"   fits 90mm-130mm OD (3.5" - 5" OD) .8
KDR004 4" 90EDFL, 92F7EDF, 92F6.65, 105EDFS, 105EDT fits 130mm-145mm OD (5" - 5.5" OD) .9
KDR005 5" 130EDFGT, 130GTX, 130EDFS, 130EDT fits 140mm-165mm OD (5.5" - 6.5" OD) 1.2
KDR006 6" 140EDF27, 140EDF4, 155EDF, 155EDFS, 160EDF fits 165mm-200mm OD (6.5" - 8" OD) 1.4
KDR7/8 7"/8" 180EDF, 180EDT, 175EDF fits 200mm-250mm OD (8" - 9.5" OD) 1.5
KDR910 9"/10" 206EDF; 10" Mak-Cass fits 250mm-310mm OD (10" - 12.5" OD) 1.9
KDR011 11"   fits 310mm-340mm OD (12.5" - 13.5" OD) 2.3
KDR012 12" Riccardi-Honders fits 340mm-400mm OD (13.5" - 15.5" OD) 2.6
KDR014 14"/16"   fits 400mm-460mm OD (15.5" - 18" OD) 4.1
KDRB20 Binoviewer Heater 1.5" and up   for eyepieces with barrel diameters over 1.5" .6

 How to Use the System

We recommend that you put your heaters in place at the beginning of an observing session and turn your controller on right away. For Premier Heaters, or heaters for Newtonian or RC Telescopes, we recommend a controller setting that represents about 20 to 40%.

If moisture has already condensed on your optics, we recommend covering the optics, turning the heaters on high and waiting 20 to 30 minutes. Once the moisture has cleared, lower your controller setting and resume observing.

The heaters wrap around your objectives, label-side out, and are held in place by elastic/Velcro attachments. The Telrad heaters are held in place with an elastic band. The heaters for secondary mirrors are placed on the backside of the secondary and can be held in place by using the polyester batting found inside the secondary mirror holder. The .965/1.25" 1.25/2" and 2" units are considered eyepiece heaters. The 1.25/2" and 2" are also heaters for camera lenses and certain binoculars.



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