[pct-l] condensation on inside of homemade tarptent

[PCT at DelNorteResort.Com (stillroaming)]

Dew is a slightly different example, but same concept. 

A volume of air contains a finite amount of water. When
cooled to a certain temp, called 'dew point', water will
condensate. When it's foggy the dew point is equal to
the air temp. The air can hold no more water at that temp. 
Dew point temp never falls below air temp. Everything in 
that volume of air will get wet with condensation; inside of 
the tarp, outside of the tarp, telescope, daisies, etc.

In the case of your telescope, the heating device you use
warms the scope, keeping a thin layer of air around the 
scope warmed slightly above dew point. No dew.

Scott

> I'm not an expert in this subject but I think you have it kind of
> backwards.  A tarp can collect an enormous amount of condensation even
> if no one's sleeping in it.  I've pitched tarps in my back yard, left
> them overnight while I slept indoors, and come out the next morning to
> find them absolutely soaked.  They couldn't be any wetter if I sprayed
> them with a hose.

> I struggle with this same phenomenon in another hobby, too.  In
> astronomy, it's a constant struggle to keep dew off my telescope lens.
> The only reliable way to do it is to heat the scope, either with an
> electric blanket type wrap, or an infrared light source, or some other
> way.

Eric