Kendrick Dew Remover System

Astro Physics 155mm refractor outfitted
with heaters for the main objective, finder
and 2" eyepiece

Kendrick Power Packs & Supply


The Kendrick Dew Remover System was developed to meet the need in the astronomical community for an effective dew removal and prevention system. This system has heaters for almost all the optical components used in amateur astronomy.

Read the May '95 review of the Kendrick Dew Remover System in Sky & Telescope

Repeated field testing on many types and optical surfaces 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

  1. It is energy efficient. Variable settings on the controller allow maximum conservation of battery power.
  2. It has an adjustable heat range to prevent tube currents or seeing degradation.
  3. It is lightweight.
  4. It is high quality
  5. It is capable of keeping every optical surface you are using during an observing or astrophotography session free of moisture all night long.
  6. It is guaranteed to work.

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The Kendrick Dew Remover System is centered around the controller. It is a compact, lightweight duty cycle switch that is fused and reverse polarity protected. The power cord is 6' long and has a cigarette lighter plug. There are four RCA jacks on the controller to plug your heaters into. With the addition of an RCA splitter cord, 5 to 6 heaters can be attached. This would allow the operator to use heaters for the main objective, both ends of a finder or guide scope and a telrad.

The box is constructed of aluminum painted black and includes a red LED to indicate whether your system is receiving power. The power output from the controller can be varied from 40% to 100%. As the controller is a duty cycle switch, it controls the power getting to your heaters by shutting it on and off many times each minute. When the controller is set on low, the heaters will continue to draw the same amount of current, only 40% of the time. Low to medium is the recommended setting for most observing conditions.

The controller is not a transformer and must be supplied with 12VDC. The controller is supplied with Velcro that will allow it to attach to your tube assembly, mount or tripod at your discretion. Box dimensions are 3.5" x 2.25" x 1.25" (1.75" with knob).

The fuse for the controller is located in the cigarette lighter jack and can be accessed by pushing in the metal pin on the front of the plug, turning it counterclockwise and then pulling it out. If the red LED fails to come on, this should be the first thing you check.

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The heaters have been built to use only as much power as necessary and thereby not waste energy. They have sponge insulation on one side to prevent heat being lost into the atmosphere. The heat is directed into the optics instead and because of this, less energy is needed to keep your optics moisture free.

The heaters wrap around your objectives, label side out and are held in place by elastic/Velcro attachments. 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" are considered eyepiece heaters. The 1.25/2" and 2" are also heaters for camera lenses and certain binoculars.

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Put your heaters in place at the beginning of an observing session with the controller at or near its lowest setting. This should be good enough for most observing sessions. The high setting is only recommended for removing moisture already collected on your objectives or for cold winter nights. If moisture has formed on your optics, put the controller on high and wait 15 to 30 minutes for the optics to warm up. SCTs should clear by then, refractors can have excess moisture removed with a tissue. You can then reset the controller to a lower setting.

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We recommend, as a minimum, that a 12 amp hour rechargeable battery be used with this system. For individuals wanting to use household current, we have a 120v converter that puts out 12v DC at 4.5 amps. We also have a converter that is rated at 14 amps output. This is recommended for anyone with large power requirements.

For information on our 12v 17 amp hour deep cycle battery see the Kendrick Power Pack.

If you are planning to use your own battery, it is recommended that a deep cycle battery be used. If you are using household current it must be transformed to 12vDC and your transformer must be rated for the amp requirements of your system : if your system draws 1.5 amps, then your transformer must be rated for at least 1.5 amps.

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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.
Telrad .88
.965" .17
1.25" .19
2" .25
3" .68
4" .85
5" 1.40
6" 1.50
7/8" 1.60
9/10" 2.0
11" 2.40
12" 2.75
14/16" 4.75
lap top Computer pad 3.17
eyepiece box heater .80
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The table below will help you to determine which heater is the right one for you scope.
.965" for .965" eyepieces and finder scope eyepieces
1.25" for 1.25" eyepieces
2" For 2" eyepieces, 50 mm finder scope objectives, smaller camera lenses. Can also be used on 1.25" oculars but a bit big. To use on 1.25" oculars just slip heater off 2" eyepiece and hang over 1.25" eyepiece.
3" will fit 3.5" to 5" OD (90mm to 130mm OD)
4" will fit 5" to 5.5" OD (130mm to 145mm OD)
5" will fit 5.5" to 6.5" OD (140mm to 165mm OD)
6" will fit 6.5" to 8" OD (165mm to 200mm OD)
7/8" For Meade 7" refractor, 7" Maksutov-Cassegrain, 8" SCT, Celestron C8, Astro Physics 7" Refractor. Will fit 8" to 9.5" OD (200mm to 250mm OD)
9/10" For Celestron C9.25, Meade 10". Will fit 10" to 12.5" OD (250mm to 310mm OD)
11" For Celestron C11. Will fit 12.5" to 13.5" OD (310mm to 340mm)
12" For Meade 12 SCT. Will fit 13.5" to 15.5" OD (340mm to 400mm OD)
14/16" For Celestron C14 & Meade 16" SCT. Will fit 15.5" to 18" OD (400mm to 460mm OD)
lap top computer heater For all lap top computers, can also be used on for desktop CPUs that are exposed to cold temperatures. Also makes a great seat warmer!
Eyepiece box heater For eyepiece and accessory boxes. Can also be used as a seat warmer.
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" I appreciate the simplicity of the operation and the power saving feature of metered heating...full on when conditions are terrible, and less power draw when conditions are border line. As we are near the coast, especially at my house from which we intend to do a lot of CCD work, your dew preventer saves the day...or should I say, night! It is amazing to see everything dripping with dew and the corrector plate on my C-11 as dry as a bone!"

Tony Hallas
"An excellent, well designed, quality product that is a much needed accessory most amateur astronomers could make use of. I use three heaters for my astrophotography and consider them essential to obtaining good results. It is worth the investment to outfit your optics with The Kendrick Dew Remover System."
Alan Dyer
" We can personally attest to the effectiveness of The Kendrick Dew Remover System as it saved the day for us at the 1993 Astrofest Convention! On an evening of good seeing, heavy dew was soaking everything. We had a chance to see what this product can do under extreme conditions. The Kendrick Dew Remover System kept our 130mm refractor free from dew until 2:30 AM when we finally decided we were too tired to observe any longer. Most everyone else on the field had dewed over hours earlier-including all our other scopes. You can be sure that we will pack a Kendrick Dew Remover System for each of our scopes when we attend the next star party!"
Roland and Marj Christen - Astro Physics
" After using the Kendrick Dew Remover System during the autumn and winter months when dew and frost are at their worst, I can't imagine anyone being disappointed in its performance."
Dennis di Cicco - Sky & Telescope, S&T Test Report - May 1994
The following letters were received over the internet.

Dear Jim,
In April 1998, Steve Mandel and myself traveled to Coonabarabran, New South Wales, Australia for two weeks of astrophotography. This trip had been planned for more than a year, with 1998 particularly ideal because of the El Nino condition. El Nino had been responsible for the severe drought conditions in Australia since 1995, making it an ideal destination for clear and dry astronomy. We purchased Kendrick Dew Removers on the off chance that we might have to use them, but all the while laughing at the possibility of any high humidity problems. The weather reports at Coona were clear skies and dry conditions, just as they had been for the last four months prior to our departure.

When we landed in Sydney, we were greeted to heavy overcast conditions that only worsened when we arrived at Coonabarabran the next evening. By the following morning we had suffered through 80mm of rain and high wind. Clouds and rain persisted throughout our two week stay. Fortunately, we had 2 1/2 nights of weather clear enough to photograph. Clear enough that is -- in 98% relative humidity!

Eta Cariane
Photo: John Gleason, Steve Mandel
Everything -- cameras, telescopes, electronics, were soaking wet within an hour after sunset. In twenty years of observing I have never attempted astrophotography in more miserable conditions of dewing, yet we were determined to get something on film. And as for the Kendrick Dew Removing System? Well, they worked perfectly! Running three heaters simultaneously at the medium/high setting, all optics were clear and dry! I've never seen anything like it. A product that worked the first time out of the box and exceeded all of my expectations with its simple attachment and function.

Jim, you are to be congratulated for your design and execution of a product that literally saved our trip from total disaster. Without the Kendrick Dew Removing System, we would have come home with NOTHING! The attached file containing an image of Eta Cariane was only made possible with the KDRS! Sincerely,

John Gleason, Steve Mandel
Equipment used with the KDRS:
6" f/7.1 AstroPhysics EDF Refractor, 80mm F/8 Vixen Fluorite guide telescope, 200mm, 165mm, 105mm, Pentax 67 camera lenses.

Dear Jim,
Your dew system performed far better than expected. Can you imagine finally receiving your new Celestron Ultima 9.25 SCT after waiting about a month and then, on the first clear night you try it out with some of your friends only to end up with your session being cut way short because dew quickly collected up on your scopes corrector plate. In fact, the entire tube assembly of the scope frosted up with dew. After several nightly tries and different atmospheric conditions, there was little difference or improvement in the situation. Dew became a harsh reality of life which I took totally for granted in the past and now, must learn to live with. After surviving the initial shock of this reality, I finally decided I had to do something about it permanently.

I received your system and preceded to install each heater. Immediately, I ran into a problem positioning the corrector plate heater onto the front cell. You see, before I ordered your system, I had already been collecting certain accessories, one of which was a counter-weight bar assembly that mounted from the front to the rear cells of the scope. The counter weigh bar, due to it*s mounting on the front cell, interrupted the position where I was instructed to place the heater strap for maximum effectiveness. Not knowing what else to do accept to remove and not use the counter-weight system, I decided to mount the heater strap just behind the front cell and onto the tube itself instead hoping that it would perform as equally well.

On the next clear night, Bill and I went out to our favorite viewing site to do some star gazing and to test out your system. Fortunately, atmospheric conditions that night were absolutely ideal for a dew remover system test. Humidity was extremely high that night and the late night air became so cool, we grabbed our jackets. Dew was everywhere and literally dripping off my car as if someone had just hosed it down for a wash. During our viewing session which lasted until 2am, I kept checking the corrector plate for any sign of dew. There were no signs of dewing even to a minor extent. The corrector plate stayed clear and dry and what brings me to telling you all this is the next statement and the whole point of this story.

*Not only did the corrector plate remain dew free and dry, the entire tube assembly of my scope remained dew free and dry all the way down to the rear cell* This is a fact of performance I did not expect at all!

Thanks for a fantastic dew fighting system. I will be recommending your system to all in need.
Russ Shettle, Camp Springs, MD.

Dear Jim,
The summers in Southwest Florida are notoriously hot and humid. Add to that the fact that our observing site is in the everglades and you can imagine the trouble we have with dew. I tried everything to keep dew off the optics of my scope to no avail. Nothing is more irritating than closing the shutter on an hour long astrophotograph only to find that at some point your corrector plate totally fogged.

That was the last straw, so I purchased one of your Kendrick Dew Removal Systems. The first night out was typical Florida. The temperature was hovering near 80, the humidity was over 90% and the dew was so heavy in some parts of the world it would have been considered rain. I hooked up the Kendrick Dew Removal system to the scope and turned it to medium low. Within thirty minutes, everything was covered in dew. Cars, chairs, other telescopes, even some of the slower moving people! But my telescope was bone dry! Hour after hour passed and it remained dry! Even during an extended picture session of the Cygnus region where the scope was pointed straight up.

I was amazed! I must admit I had my doubts that it would work. Now I feel you may have understated the capabilities a little. If it can work that well in Florida where summertime humidity reaches 90% and higher at night, it can work anywhere. I no longer worry about dew ruining my night, that problem has been eliminated. Do you have anything for Mosquitoes?

Thanks for saving my summer time observing.

Feel free to post this letter along with my e-mail address ( ) on your web site. I would be happy to tell people how well the system works!
Michael Walsh, Southwest Florida Astronomical Society

After using a number of your products over the past few months, I thought I'd drop you a note about their performance.

The "Observer" tent: What a luxurious way to observe the sky in remote locations (or a backyard)! I had the tent assembled in under 15 minutes and my LX200 12" with its attendant gear fit perfectly. I cannot say enough about the convenience of the two-room design. Placing my cases, charts, sleeping bag, etc., in one room and having an uncluttered environment in the 'scope room makes observing not only convenient but pleasant. The tent has been a godsend on windy nights or when the idiot next door turns on that annoying porch light. When I took it to Vermont a couple of months ago, it felt like the equivalent of staying at the Ritz. Well done! All it needs now is the Kendricks Inflatable Jacuzzi.

Dew Remover: Quick to install and quick to respond, the Dew Remover has made all-night observing possible here in humid New Jersey. My first experience with the system occurred on a very moist night. My LX200 12" was beginning to show signs of condensation so I attached the Dew Remover. After less than two minutes, I had the 12", 2", Telrad, and Keypad (which I used on the oculars not in use) heaters in place and the dew that had begun to collect was vanquished a minute later. The Dew Remover system saved the day (night)! I've also used the 2" heater to keep my coffee cup warm on chilly, dew-free nights. It works!

Kwik Focus: The Kwik Focus has become an integral part of my nightly observing. The simplicity of the design makes it easy to use. And, does it work? You bet! During the recent occultation of Aldebaran (9/12/98), I used the Kwik Focus on a fifth magnitude star to get what I thought would be a rough focus. I was observing with my LX200 and an Astrovid 2000 video camera. When I slewed back to the Moon, it was in perfect focus! I have never seen a video image of the lunar surface with such detail! I also use the Kwik Focus in conjunction with an SBIG ST-7 CCD camera. On several occasions, I was able to use the Kwik Focus without further adjustments to achieve tack-sharp images. I have also made a 10mm hole in one of the three plugs to use during planetary and lunar CCD work, to stop down the light. There are only two drawbacks to the Kwik Focus that I need to mention. First, it does not fit over the Meade dew shield (you must remove this to use the Kwik Focus). And, secondly, stray cats will find the three removable plugs a necessity to play with while you're observing on your front porch. Take precautions.

Off-axis solar filter: The 82mm off-axis solar filter is incredible! My first use involved videotaping sunspots and a couple of bright limb flares. The detail was phenomenal. Using the filter for visual observations was also incredible and I was pleased with the detail and color afforded by the filter, even at extremely high magnifications. Since it is affixed to the Kwik Focus and used during the daytime, the issue of the Kwik Focus not fitting over the Meade dew shield becomes mute. I have also removed the solar filter (quickly unscrews from the mount which is very convenient) and used it with my Swift 20x.80 wide-field binoculars, well, MONocular, in this case. All in all, a superb product for solar observations.

12v 34AH battery:I cannot say enough about this superior power source. When it first arrived, I thought I should field test it (essentially, beat it up). I had the LX200 12", all four of my dew heaters (on maximum), a lap top, a SCSI/parallel adapter, the Astrovid 2000 video camera, a Toshiba video monitor, an SBIG ST-7 CCD camera, and a CD player all connected to the battery and the 110v inverter. Even with all that current being pulled, I was able to observe for nearly three hours! On subsequent nights, I've been a tad more conservative and have had the 'scope and heaters last all week long before needing a recharge. The charge indicator is a great convenience, as well. I have not used the high output connections yet, however, I am considering using it to charge an electrical fence to keep those stray cats off the front porch.

All in all, Jim, I am very impressed with the quality of the workmanship and the functionality of all the products I've received from you. If they ever bestow a Nobel Prize for astronomical products, you would be a most worthy recipient.

If any of your potential customers would like to contact me regarding the above mentioned gear, please don't hesitate to give them my e-mail address,, as I'd be happy to share what I've learned about the Jimi Kendricks Experience.
George E. Mahlberg....Princeton, NJ

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