Astrozap Two channel/four output dew heater controller


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This Astrzap dual channel controller will independently control the power going to two dew heater strips per channel, for a total of four dew heaters . . .
Our Product #: AZDHCB
Astrozap Product #: AZ-720

Product Description

The Astrozap dual channel dew heater controller is simple, easy to use, compact, and lightweight (only 7 ounces). Its heavy duty plastic case measures 3.5" square by 1.5" deep (2" counting the two control knobs). It is supplied with a 2" Velcro strip for easy attachment to your telescope. There is a green LED indicator to show when the controller is getting power.

The controller has a fused male cigarette lighter plug on a 6' long cord. This allows you to connect it to a car's cigarette lighter plug or (preferably) a rechargeable 12V DC battery (to avoid accidentally draining your car battery and leaving you stuck at your dark sky site after a night of observing). The fuse has a 5 amp rating, the maximum amperage capacity of the controller.

There are four RCA output jacks on the controller into which you can plug your heater strips. All heater strip brands will work, in addition to Astrozap heaters. There are two control knobs, one for each channel. Each knob controls the power going to two of the four 12V outputs. For example, this allows you to use the two outputs of one channel to power the heaters for the main objective of a small scope and a laptop computer's LCD screen, while the second channel can be used at a different power setting to control the heaters for a Telrad and an eyepiece. With the addition of an RCA splitter cord, even more heaters can be attached, as long as you don't exceed the maximum output capacity of the controller.

The controller uses Pulse Width Modulation technology to control the power going to your dew heater strips by turning the power on and off many times each minute. When the control knobs are set on medium, for example, the heaters draw the same amount of current whenever they are on, but they are on only 50% of the time. The power output from the Astrozap controller can be varied over a 5% to 95% duty cycle range. When the controller knobs are set at their lowest settings, the controller is effectively off. Two amber LEDs indicate the power level of each channel. The brighter each glows, the higher the duty cycle for that channel's two outputs. Low to medium is the recommended setting for most observing conditions. The controller is RFI (radio frequency interference) free, an absolute necessity if you are going to be doing digital imaging.

Owners of 12" and larger SCTs may need two controllers - one for the main objective heater and a second for any other heaters you wish to operate. The heater strips for the objectives of these size scopes can nearly max out the power output capacity of the controller by themselves.

Tech Details

Warranty 1 year


Review by:
I live in the southeastern US where dew is particularly problematic, and I use this unit routinely with great success. I like the fact that it has independent settings for 2 sets of two power outputs - provides a bit more versatility in controlling dew on separate optical elements. I highly recommend this product. (Posted on 10/28/2019)
Review by:
Scope, finder, eyepiece and one strip in the eyepiece case is how I usually go out with this setup. I have never had a dewing issue this way, except for the mount. Careful adjustment is required to keep it from using too much battery, but other than that, its flawless. Highly recommended! (Posted on 10/27/2019)
Review by:
I have been using this dew controller for many years and it has never failed me. I have 3 heater strips and it controls them all at the same time with no issues. Highley recommended. (Posted on 1/8/2019)
Review by:
This controller has been a good one. Really like that you can have two different settings so you can manage power consumption. Although the only flaw I've notice so far is the size. I feel like they could have made it a little smaller so I can mount it on more different places if need be. (Posted on 1/7/2019)
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