Re: Looking for help finding a dew heater

On 2007-12-03, astrophotography@xxxxxxxxx <astrophotography@xxxxxxxxx> wrote:

I've Googled around a bit but couldn't find what I want. I'm also
hopelessly incapable of making this myself.

Anyone know where I could get what I have described? An AA battery
powered dew heater for eyepieces only. Thanks for any help.

A home made resistor based dew heater is trivial to construct, it
is merely a case of soldering a few resistors together and attaching
a lead. If this is really beyond you I'm sure you know someone
who could do the work for you - it is only a ten minute job. There
are various guides available on the net, e.g.
http://webhome.idirect.com/~rsnow/resister.html

However, using AA batteries probably isn't a good idea as the
batteries are too low capacity (in general anything designed to
get hot uses a lot of power). Even if you restrict the power output
to 1W that would drain a single AA battery (alkaline or high-capacity
rechargable) in three hours or less, and I suspect you will need
at least the option of more power than that. Bigger batteries are
likely to prove much more usable in practice.

--
Andrew Smallshaw
andrews@xxxxxxxxxxxxxxxx
.

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