(meteorobs) Heat required to prevent dew in a box for allsky camera

[James Beauchamp]

Maybe it's just my bad luck :)

One other thing (a little off topic), as an EMI/EMC engineer I suffer from an arguably irrational fear of lightning.  The obsolescence of the low light camera and anything currently available with compatible performance, and a 20m dipole over the camera didn't help.

(I've got a few lightning compilations on the YouTube page - including one strike to the next door neighbors house!)

I added AC Zener diode, MOV, and an electrolytic cap to the DC input.  Plus a few ferrites on wires feeding the main unit.

Sent from my iPhone

On Nov 22, 2014, at 3:50 PM, Chris Peterson <clp at alumni.caltech.edu> wrote:

A good ball bearing fan should last for years. In fact, in more than ten 
years and dozens of cameras we've never had one fail. If the fan were to 
fail in one of my cameras, all that would happen is that the dome would 
be susceptible to dewing. It couldn't result in an ugly failure of any 
components or melting of the dome.

Chris

*******************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

> On 11/22/2014 1:37 PM, James Beauchamp wrote:
> The fan does a good job of moving the air, but they fail about every six months in mine, resulting in uneven heating.  Before reducing the heat, the natural convection in a failed fan situation caused it to melt the acrylic dome in two distinct spots.
> 
> I did send a recommendation to put the resistors in series, or increase their value to bring it down to 20 watts or so.
> 
> I bought a small lot of 2" fans from All Electronics and check it regularly.

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