From: Milton Aupperle <milton@outcastsoft.com>

Date: August 3, 2012 1:21:41 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Cooling Fins

Hi Dave;

Nice design.

In summer time - especially when I am out at the lake - the outside of my camera would drip with water when cooled. To combat that I would wrap the camera in saran wrap (i.e. vapor barrier) before attaching it to the Cooler with straps, which kept it dry. Eventually, I wound up using flexible foam packing as insulation around the camera, which not only keeps it dry, it also helped trap the cooling too.

The other thing I do now is to leave the cooler off and then run the camera for about 10 minutes so that it gets warm / hot. That dries out any moisture in the camera and the filter wheel area etc. I do this about an hour before I start imaging, and then 30 or 40 minutes before I want to start, I start the cooler back up to cool the camera down. Also I cool it down with the camera not powered up, so it cools off faster.

As far as a CCD chamber, if your using a 1.25" nose piece you can probably thread an clear glass filter in it, which will add dead air space in front of the CCD. I have a 2" LPR filter in front of my FilterWheel which helps seal the camera off from the outside air.

HTH..

MIlton Aupperle

On 2-Aug-12, at 7:44 PM, Dave Goodyear wrote:

Hi Guys.  Seeing Milton’s cooler made me cool my GrassHopper Express 2.8mp.  During solar my camera would easily hit 135-140F.  With the dual cooler my camera now shows through AstroIIDC as around 74.2F.  I just finished this mod yesterday.  Just like Milton, different voltages and amps vary the cooling.  I have found that 8v is the ideal voltage for the dual coolers.  @12v it pulls 5 amps  @14 it pulls 6amps.  At 8volts its pulls around 2.5/3 amps.  One amp for the fans.

Now I do know that the coolers are cooling the case way below ambient temp and the dew point.  I live next to the ocean in southern California and my humidity is always very high.  Especially at night.  The case will start to form a lot of water.  My plan is to either wrap the camera more, add a timing circuit, or seal the camera in a box except for the nosepiece and fill with Scuba air (Scuba air’s dew point is -56F)  Scuba air works very well when the front glass of a camera dews up.  I can use a ccd chamber sealer and seal the front of the CCD with scuba air and the ccd sealer.

I was able to pick up ten 30mm x 30mm peltier coolers with heat sinks on ebay for $20 and six maglev 40mm x 40mm x 28mm fans for $15. I use Anderson Powerpoles exclusively with my tele power as well as other areas so I have extra “poles”.

The Reflective insulation was something I added a little bit ago without testing.

Here are a few links to pics.  The second one is not in focus all that well:

http://ns1.kb2networks.com/GHXPeltier1.jpg

http://ns1.kb2networks.com/GHXPeltier2.jpg

Dave Goodyear

KB2 Networks Inc.

214 Main St. #318

El Segundo, CA  90245

310-933-2436

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