Dew - home made solutions?

I know this is a typical newbie question but I was wondering if anyone knows any quick "home-made" solutions that will counteract dew forming on my scope?

I have heard that draping a towel over the scope is supposed to help, but I haven't actually tried it myself. Is that a myth or does it help?

Any tips much appreciated.

Following on from this, I will eventually put my hand in my pocket to buy a proper solution, so any advice here is also much appreciated. I don't know anything about anti-dew solutions.

thanks.

A hairdryer on its lowest fan speed and a cool setting will definately work.

The towel solution sounds like a myth...

Keith,

I've built a dew controller with pretty much everything thats on the hi-end kendrick digifire. If you are good with a soldering iron I'll have all the details, schematics etc ready in about 1 week or so. You can choose to buy or make the heating strips too, however I recommend you probably buy them. The dew-not ones are cheap and much better than anything you could easily make. Unless you are a sado-hasochist who enjoys stiching metres of nicrome wire into fabric.

The heating strips can also be made out of resistors. This is easier to do but has the disadvantage that the heating is uneven across the optics.

The controller I designed has 4 outputs and two temperature sensors so that the heaters only turn on when the optical temperature drops close to the ambient. You can set the power in steps of 10% from 0 - 100 for each channel.

Following on from this, I will eventually put my hand in my pocket to buy a proper solution, so any advice here is also much appreciated. I don't know anything about anti-dew solutions.

Keith - your final solution will depend on what you want and how much you want to spend. I have a Kendrick system which works quite well though it struggles with a C14. I use it because it is EM shielded and controlled remotely by PC. It's very robust and so far unharmed by the element. Its quite power hungry though.

There are much cheaper solutions, including homemade ones - others will fill you in on their picks of the crop...

Cheers
Dave

Keith,
Basically dew forms on the corrector plate when it cools to below the dew point, so the trick is to keep the corrector temp a little higher, so putting a towel over the top of the scope slows its cooling, this might work but might cause thermal currents in the scope to last longer.
So what you want is a way of "heating" the corrector plate a little.
I built a temperature controller with details here
www.irishastronomy.org/boards/viewtopic....highlight=dew+heater

You can make a belt by placing resistors in series or buy a kendrick belt.

Thanks for all the replies - lots of helpful info there.