Dew Control DIY in a hurry.

[Nico13 (Ken)]

Haven't bothered with dew control up till now but as I'm getting more serious about imaging I'm sick of taking shots only to find the corrector plate was half fogged up.

Well after looking around IIS for some info I decided on the DIY unit here http://www.backyard-astro.com/ and then with the weather looking a bit sad for SVAA camp this weekend I figured I better pull the digit out and do something about it.

So after a trip to Jaycar who only had half the bits and then not the exact ones needed a bit of a hunt around the shed I found enough bits in the old projects box to put this together.

A couple of hours or so later and a stolen plastic box from the kitchen cupboard I had this little baby up and running with two parallel out puts.
Need to tidy it up a bit but the nicrome wire heats up nicely, I may not use the teflon tube as it doesn't transfer the heat well.
I may just make an insulated strap of some sort, something simple to see how it performs.

Total cost so far about $25.00, not bad hey.

Will let you know how it goes.

[DavidU (Dave)]

Nice work ! Love the plastic container, easy to open & fix too.

[stardust steve (Steve)]

looks like a good little project for the cloudy nights. Good info

[Shark Bait (Stu)]

I have just had to pull the pin on tonights observing session. The condensation build up beat me and it is the first clear night we have had for quite a while. This is the first time I have had this problem since owning the Dob.

I decided to check out the IIS forum and the inspiration for my next DIY project has been posted.

Keen to hear how your new kit performs.

[RAJAH235]

Ken,
You might like to try a string of resistors of say, 1 Watters in series & see if they will fit inside silicon fuel tube. (From a radio control/hobby shop.)
It does come in various sizes but I haven't bought any for years, so.......?

"r" Value of each & how many you want = depends on total "R" value of your nichrome.
Maybe 10 or so?

Just an idea.

I made a heater for my Dob's 2ndary that way.

You could also try some heater wire from an old electric blanket.

or a string of 1 or 2 Watt resistors in parallel, using de-soldering braid as the +ve & -ve conductors.

Lots of ways to do it.

[rcheshire (Rowland)]

Hi Ken. It was good to see the dew heater in the flesh, so to speak. And, I think, a solution to low pass filter defogging on my dslr cooling mod.

Question is, how much power is required to warm an area of glass the size of a postage stamp - very little, I think.

I might start another thread when I have done more research.