[okiscopey (Mike)]

My last observing session (Kulnura) was cut short by dew problems, so I've ordered one of those diddy little 12v hair dryers for the EPs and a dew-zapper from Bintel which fits on the front of my ETX125.

It seems these zappers need a controller, but they're a bit pricey.

As I already have a Jaycar digital thermometer which reads the temperature difference (to 0.1 deg. C) between two K-type thermocouples, so my cheapskate plan is just to keep an eye on the thermometer and simply switch the zapper off when temperature between the corrector and the night air is in the right range.

I'm not imaging, just doing general observing, and all of this is just the learning curve for hopefully bigger and better things.

Can anyone help with these questions:

1. Will this 'manual control' work reasonably well, or will the temperature swings be uncontrollable?

2. What is a workable temperature range? I understand if the corrector is the same or one or two degrees warmer than the air, dew won't form.

3. I only have a 7Ah battery but the zapper draws a couple of amps. Any guess as to the likely percentage of time it'll have to be on in Kulnura-type conditions?

4. How and where is the corrector sensor fixed?

Any links, comments or ideas will be gratefully received!