[Chaos-l] dew prevention advice

[Robert Nielsen]

Michael,

Note: There was an article in the September issue of the CHAOS 
newsletter about Jon Stewart-Taylor's homemade Telrad dew zapper ... 
perhaps that is what gave you the idea of building one yourself.   The 
article gives a good explanation of his experience (which is positive) 
and also some links to useful web sites (like the ones that help you 
figure out the electrical formulae you will need).

Personally, I've had both Kendrick and Dew Zapper equipment.   The 
"control unit" I have had from the beginning is the Kendrick one, and it 
seems to perform flawlessly.   The actual straps/bands are a different 
story altogether.  Three of the four Kendrick ones I originally bought 
all failed at the same time one night at a previous MASP (5 years ago?) 
and left me without a useful scope for observing that night.  Luckily, I 
could just wander over to vendor tents the next day and buy some 
replacements, which happened to be Dew Zapper straps.   They have worked 
ever since.  So I would recommend the Dew Zapper bands ... and (because 
it has worked for roughly 10 years) the Kendrick control unit ... 
although you have a control unit already on your scope, right?

Robert

Michael Hrivnak wrote:
> It's time for me to buy some dew prevention for my Starmaster 18.
>
> First off, I am strongly considering building my own heating elements by 
> following these instructions:
>
> http://www.dewbuster.com/heaters/heaters.html
>
> Rather than lay out $120-150 on heating elements, I think I can do it all for 
> under $20.  Have any of you done this before?  Would anyone be interested in 
> making some with me?  The resistors are real stinking cheap ($0.016), and 
> shipping is really the greater cost (at about $5 for as many as you can buy).
>
> As for a controller unit, what do you suggest?  Lots of people praise the 
> DewBuster for its intelligent thermostat, but I'll mostly not be using that 
> feature.  On the Starmaster, I'll just use it to heat the finder, telrad, 
> eyepiece, and secondary mirror (which already has an AstroSystems heater that 
> includes a thermostat).  However, I may want to use it on my refractor down 
> the road, in which case the thermostat ability would come in handy.  Any 
> opinions or experience to share?
>
> Thanks,
> Michael
>   
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