Because it is either frosty cold or heavy dew at night it is always likely that frost or dew will build up on the front element of a telescope making it useless.
So it is necessary to lightly heat the scope or lens just enough to keep the frost/dew from developing.
The main controller (12 volts) can run up to 4 heating strips, each one independently controlled.
I purchased this one from Thousand Oaks through Amazon for $113 (https://www.amazon.com/gp/product/B0033UKAFO)
I spliced the RCA cable to expose the wires...
added some solder to them, wrapped them around the wires and soldered them in place (as best I could)
Then the "wrap up"...
Then finally adding some velcro strips to wrap and hold the heater in place...
I tested this on the heating controller and learned that I had to set it on the lowest temp setting to give the proper amount of heat without it over heating the wire and tape (test yours carefully!)
Here is the final product wrapped around the lens:
Obviously the cable is short but I will be using a RCA video extension cable when the camera is piggybacked on a scope or attached to a tripod.
The Good News: First, it just works and secondly, I can make as many as I want for nearly nothing!
So it is necessary to lightly heat the scope or lens just enough to keep the frost/dew from developing.
The main controller (12 volts) can run up to 4 heating strips, each one independently controlled.
I purchased this one from Thousand Oaks through Amazon for $113 (https://www.amazon.com/gp/product/B0033UKAFO)
Then I ordered the dew heater from DewNot for my 8" Meade LX200GPS scope through Amazon for $55.00 (ouch!) https://www.amazon.com/Dew-Not-Heater-Strip-DN009/dp/B003V36ZMK
They work great... but the heating strips are a bit expensive...
...so I discovered that it is possible to make one at home more inexpensively!
I purchased some Nichrome wire (https://www.amazon.com/Dew-Not-Heater-Strip-DN009/dp/B003V36ZMK) for $6.49
I grabbed some ordinary duct tape, a ruler, an old RCA audio cable, scissors, solder & soldering iron and got to work...
First I measured the diameter of the scope or lens using a cord to determine the approximate circumference, in this case I was making one for my 55-250mm Canon zoom lens and I used the RCA cable...
Pulling out some duct tape I measured the needed area for the heating wire...
Next I laid out the nichrome (heating wire) on the sticky side of the tape. Since the area I need to heat is very small I will be putting the wire on 1/3 of the tape and then folding the tape over in thirds. I left plenty of wire available for needed connecting to the RCA cable.
December 30, 2017 UPDATE: the less wire you use the HOTTER and more quickly it will get hot... and that is not always a good thing! I used too little wire in this test and when I added the power it got hot, really hot! But I was able to turn down the rheostat to keep it from overheating. So it may be better to use more and then turn up the rheostat than to have it too hot at the lowest setting. This may require you to create another heat strip... but at the cost of redoing it, it is a no-brainer.
added some solder to them, wrapped them around the wires and soldered them in place (as best I could)
Then the "wrap up"...
Then finally adding some velcro strips to wrap and hold the heater in place...
I tested this on the heating controller and learned that I had to set it on the lowest temp setting to give the proper amount of heat without it over heating the wire and tape (test yours carefully!)
Here is the final product wrapped around the lens:
Obviously the cable is short but I will be using a RCA video extension cable when the camera is piggybacked on a scope or attached to a tripod.
The Good News: First, it just works and secondly, I can make as many as I want for nearly nothing!
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