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Post by Deleted on Feb 3, 2014 12:37:05 GMT
Hey guys,
So i decided to change the power to my dew heater from the battery to the mains. I just snipped the cigarette lighter plug off the cable and added a wee 2.1mm plug thing. Anyway... while doing some quick tests to check everything was working ok i left it on for about 20 mins while i got food etc. Came back and everything was fine...except the heat of the dew heater! (it is something i noticed before when using the battery too but didnt care as it was setup and i just wanted to look at stuff)
It was very very hot! Like if it was just a metal strip with no material on it...it would burn my hand. Maybe its meant to be that hot i dunno? I did feel the inside part that holds the glass (that has the scope details on it... f/10, 2000mm etc) But thats seemed fine to be honest and wasnt very warm.
Do you think i have anything to worry about? Should i invest in a dew heater controller maybe?
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Post by johnno on Feb 3, 2014 12:47:31 GMT
I've wondered how hot it should get to, mine get hot/warm I can hold them and not get burnt. I use a band for the ed80 and a astrozap dew shield with heater for the mak and they seem to give out the same amount of heat. I use a LED light dimmer as my controller so maybe this is not letting it getting to hot
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Post by Deleted on Feb 4, 2014 0:01:47 GMT
Hey guys, So i decided to change the power to my dew heater from the battery to the mains. I just snipped the cigarette lighter plug off the cable and added a wee 2.1mm plug thing. Anyway... while doing some quick tests to check everything was working ok i left it on for about 20 mins while i got food etc. Came back and everything was fine...except the heat of the dew heater! (it is something i noticed before when using the battery too but didnt care as it was setup and i just wanted to look at stuff) It was very very hot! Like if it was just a metal strip with no material on it...it would burn my hand. Maybe its meant to be that hot i dunno? I did feel the inside part that holds the glass (that has the scope details on it... f/10, 2000mm etc) But thats seemed fine to be honest and wasnt very warm. Do you think i have anything to worry about? Should i invest in a dew heater controller maybe? Hi Chris,
This seems dodge to me! Mine never get above luke warm and sometimes I question if they're even on but they do the job!
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Post by johnno on Feb 4, 2014 0:19:54 GMT
That's how mine are, they have to be on for some time before you can get any heat out of them
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Post by Deleted on Feb 4, 2014 0:54:24 GMT
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Post by johnno on Feb 4, 2014 0:56:10 GMT
Nope, but that looks cool
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Post by Deleted on Feb 4, 2014 0:57:30 GMT
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Post by Dragon Man on Feb 4, 2014 9:05:49 GMT
Heater straps should never get hot. The shouldn't even be warm to the touch.
Their whole job is to increase the temperature of the telescope area behind the Primary lens by only 2 or 3 degrees. That's all it takes to prevent dew depositing on the lens.
The strange thing about lenses and cold air is that it might be 5 degrees celsius Ambient, but because a lens is looking into the extreme cold of space it will drop to a temperature below ambient (don't ask me how or why this happens because I don't understand it either) and that is why lenses attract dew, by water vapour condensing on the lens because it is colder than the surrounding Ambient air. But by simply elevating the temperature of the lens even by only two or three degrees above ambient it will not allow dew to form.
When I wrap my hands around my heater straps I can barely feel any warmth. They feel cool, but the scope itself feels colder.
A good way to tell if they are working correctly is to wrap one around your wrist, and if after a few minutes it barely feels warmish (only about 2 or 3 degrees warmer then your skin) then it is perfect.
On a night when the Ambient temperature is minus 5 celsius the heater strap will be about minus 2 degrees, not warm.
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Post by Deleted on Feb 4, 2014 10:11:59 GMT
Ok i think its fair to say that my heater is running waaaaay to hot then! I have bought one of they controllers above...hopefully will do the trick.
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Post by Deleted on Feb 4, 2014 20:40:01 GMT
I bought a couple of these last year to control my dew straps. You can dissmantle them and build them all into one neat box if required. dimmer controllerReally hard to go wrong at that price.
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Post by davy on Feb 4, 2014 20:47:57 GMT
Cracking price for them allan.
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Post by Dragon Man on Feb 5, 2014 8:23:21 GMT
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Post by johnno on Feb 5, 2014 9:49:37 GMT
yep, that's what I use
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Post by Deleted on Feb 5, 2014 11:37:03 GMT
Now that is a bargain Ken, and whats more, they actually work.
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Post by Deleted on Feb 6, 2014 12:26:03 GMT
Just to let you guys know. This little guy arrived today and seems to work perfect! My dew heater now runs at a normal heat and can be adjusted remotely
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Post by Dragon Man on Feb 6, 2014 13:49:33 GMT
I have just ordered 8 of them A whole total of $25 Aussie Dollars. ($22.40 US Dollars, £13.70 UK Pounds) I ordered so many so I can make free Scope Heater kits for other people.
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Post by Deleted on Feb 6, 2014 14:29:48 GMT
Some excellent finds there "ya couldnt even make them for that price"
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Post by Dragon Man on Feb 6, 2014 14:35:56 GMT
Just to let you guys know. This little guy arrived today and seems to work perfect! My dew heater now runs at a normal heat and can be adjusted remotely Excellent idea Chris. Clever boy
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Post by Deleted on Feb 6, 2014 21:32:09 GMT
Some excellent finds there "ya couldnt even make them for that price" But the funny thing is....somebody actually does.
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Post by Deleted on Feb 6, 2014 22:11:03 GMT
Just to let you guys know. This little guy arrived today and seems to work perfect! My dew heater now runs at a normal heat and can be adjusted remotely Hi Chris,
I see this has a dc socket did you have to switch the plug on the heater? I say this as my heaters have a phono type plug. I have a spare heater I was planning to use on the scope cam lens but had nothing to plug it into so this little gadget might do the trick.
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