Dew heater advice please

[Spookyer]

Hi all, my scope is arriving soon (132mm refractor) and I believe I will need a dew heater.

I have never used one before. I guess I also need a heater for the finder scope and maybe one for a camera lens that I might mount over the main scope at times so I guess atleast 3 units.

Looking online you seem to buy a control box and then plug the individual strips in?

Any recommendations on brand or where to purchase?

I have a 24Ah battery to run it on.

thanks
Brett

[barx1963]

I have used Kenrick straps and controllers and found them excellent. The only slight issue I had was the velcro tabs that hold the straps closed can come loose with use.
The controllers themselves are easy to use and reliable. I have a Digifire 7 (see http://www.bintel.com.au/Accessories/Dew-Control/Controllers/Kendrick-DigiFire-7-Digital-Controller/40/productview.aspx) and it has 6 outputs. Four are adjustable in 10% increments while 2 have full power.

Malcolm

[louie_the_fly]

If you're half handy with a soldering iron, and have a wife that can run a sewing machine and a hot glue gun, they are really easy to build. You can download an excel program for working out how many resistors to use. I made 1 for OTA, 1 for finder & 1 for my diagonal. I don't use a controller with them. They seem to put out the right amount of heat to keep the optics clear, but not enough to heat the optics up. I think my OTA heater is 12 watts, & about 18 watts total for the 3. I have a 17aH battery that runs them OK. Just need to be careful when using them as the wire on resistors is very thin these days.

I put an LED on my OTA one because a) you know it's on, & b) it looks hi-tech to people who don't know anything about astronomy kit.

Have fun.

[acropolite]

I built a single output controller, works very nicely, but I ended up buying a Thousand Oaks 4 channel controller rather than stuff around building more. http://www.myastroshop.com.au/products/details.asp?id=MAS-078A
Dew strap prices are obscene here in Australia, I bought mine from Dew-Not (http://www.dew-not.com/Order_Form.htm) in the US.

[Spookyer]

Thanks, have ordered a Thousand Oaks controller and some heater strips.