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Old 05-10-2019, 01:33 PM
Sunfish (Ray)
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DIY cooling

I have been thinking of glueing one of these to an aliminium plate and threading on to the back of my secondhand uncool ASI1600.

https://www.adafruit.com/product/1335

Might be an interesting project if it works well enough . I will need a vspour barrier insulation sock for the camera and some heat conducting adhesive along with a fabricated aluminium plate, peltier and control device, or maybe just on/ off.

Any thoughts on whether I could create condensation inside the ASI? Perhaps it would seal well enough.
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Old 07-10-2019, 08:27 PM
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doppler (Rick)
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I made one of those for my DSLR, I am using an OAG now so it doesn't fit on my DSLR anymore. It screws onto the bottom of the camera, I'll give it a go on my 120mc and see how it goes.


Ok I tried it out for an hour, the temp went from 26 deg to 11.7 deg in 30 mins and then stayed at that temp for the next 30 mins. The outside case and nose cone had a lot of condensation but the optical window seemed fine. A partial success but I think that the condensation might become a problem during a long session.



Rick
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Last edited by doppler; 07-10-2019 at 10:33 PM.
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Old 08-10-2019, 07:46 AM
glend (Glen)
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Cooled 1600s have dessicant inside the sensor chamber, and the chamber is sealed with O rings on the cap and glass window, the uncooked cameras obviously don't come with dessicant provisions. You could try flooding the interior with a dry gas, like Argon, which you can buy at Bunnings, but it would not last very long imho due to being heavier than air and leakage eventually. Pretty sure that what your suggesting has been tried many times before, and a search here and on the Cloudy Nights forum will probably be very instructive.
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Old 11-10-2019, 07:33 AM
Sunfish (Ray)
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Thanks for the replies and for the images and tests Rick. I think that any reduction at that level would be worth the trouble for $60 and a fun project. I think the preassembled adafruit model may also be a little more efficient.

Have you measured the temp simply by looking at the reporting in the capture software?

I have looked at a few different DIY projects. The argon idea is a good one.

I also imagine that condensation can be ameliorated by sealing the whole assembly with a moisture proof bag , insulation and desiccant set in the glue/epdm layer and possibly heating of the camera front connector so there is a temperature gradient from ambient at the front to very cold at the back of the camera.
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Old 11-10-2019, 08:33 AM
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doppler (Rick)
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Hi Ray,

I was just going of the sensor temp in the capture program. I think the dedicated cooled cameras only chill the sensor whereas the diy model cools the whole casing. The temp of the TEC module is controlled by the power source, in my test I was running it via a usb phone charger. Its a 12v module so upping the voltage from 5v to 12v should increase the cooling power. If you hunt around on ebay you will be able to find a unit for a fraction of the adafruit price, mine cost around $10.
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Old 22-10-2019, 11:31 PM
Jasp05 (Aaron)
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I was just about to start a thread about my foray into this exact topic.

Just tonight I put a 12706 TEC Module onto the back of my ASI120mm.

I am testing cooling capacity of heatsinks etc before I go and attach it all to my dslr.

I was running 12v on the peltier with a low profile heatsink from an old computer graphics card. (the last photo)

Ambient temp was 25 deg C. Heatsink temp rose to 28 deg C and the Sensor temp as reported through APT was down to 6.5 deg C.

I did use an old stubby cooler to insulate the body of the camera. Wrapped with electrical tape to hold it in place for now until I can fabricate a proper one. But no moisture was on the body of the camera, and the imaging sensor never fogged over either. Nor was their any evidence of that beginning to happen.


So that was 18 degrees below ambient cooling. I do need to still work out a way to mount the heatsink to the peltier and camera and that might help cooling slightly if there is more contact pressure to help transfer the heat.


Here are some images from 30sec darks showing the difference from ambient to cooled. Will have to try longer exposures and see the difference on them also. Tried to convert from Fits to Tiff and then exported to Jpeg. Will have to find a better way to convert, but you can still see the huge difference in shots.


I did some initial test using only a small 40x40x11mm heatsink with a 40mm fan. Was trying to see if it was viable to make it as small as possible.

12v would overload the heatsink so settled on 7v. This reduced the sensor temps to around 8-10 deg below ambient. 25deg ambient to 16 deg on the sensor.
I've attached some photos of the 3d printed holder bracket I designed.

Given the simplicity of this smaller heatsink combo and a 10deg drop in temps would still be worthwhile mod.
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Old 22-10-2019, 11:42 PM
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Just be careful not to cool any part of the camera (not just the sensor) below the dew point or you will get condensation inside. These cameras are not sealed.
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Old 23-10-2019, 09:21 AM
Jasp05 (Aaron)
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Quote:
Originally Posted by luka View Post
Just be careful not to cool any part of the camera (not just the sensor) below the dew point or you will get condensation inside. These cameras are not sealed.

I plan to open the camera to put a conformal coating on the pcb's and add a dessicant in the body if there is room. I had mine sitting at 6 deg when the dew point is 15 deg, and as mentioned there was no sign of condensation in the body.
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