My Ice water Canon t3i/600D cooling project

[dts350z]

One of the users asked me to start a thread on my ice water DSLR cooler project.

 

See the linked pdf: http://glenn.ws/web/images/AstroPhotography%20Hardware%20Projects%20-%20compressed.pdf

 

Beware for the guide camera cooling, because I didn't have the insulated bag with cooled air for the guide camera, I had a ton of condensation and eventually killed the camera (fortunately repaired under warranty). I have since made a small bag with cpu cooler and water block for the guide camera, but I haven't deployed it yet. Again, with this project I have ZERO condensation in the DSLR camera bag.

 

I had purchased a bunch of reusable silica gel desiccants, but despite picking one with good reviews on Amazon I could never get to recharge and I don't use it.

 

I have since switched to a bigger cooler for the ice/water, so that I can put in 20lbs of ice and have it last all night.

 

More recent Pics:

 

   

 

 

[ZeroID]

Hit your copper with a blow torch till nearly red then let it cool slowly. It will be soft as butter almost. Your Copper is workhardened by bending and the rolling process when it is made.

 

Ice and water and especially salt seem a rather dangerous mixture to have near electrical situations. Why not use a Peltier TEC element on a finger or cold box ? We're acheiving temp drops of 16-20* with good control from a 50 watt unit and using a largish but lightweight server CPU thermosiphon radiator assembly I chopped all the heavy heatsink base off and reduced it to just the copper contact plate and the radiator fin assembly. On the ZWO ASI 120 with metal to metal contact I can easily get down to - 6* C.  12 volts at about 4 amps power consumption and no ice or cold water to put your foot into. A TEC costs less than $10, cheaper than buying ice bags as well.

Performance in a cold box and DSLR not so good but with a cold finger is excellent.

[dts350z]

If I had started with the cold finger I probably would had success with the TECs that I had.

 

Without the cold finger I had no way to get that small cooling power effectively to the camera sensor.

 

Also, to control condensation, I think it's critical to cool the air around the camera as well, so maybe one tec for the camera and one for the cold box?

[ZeroID]

If I had started with the cold finger I probably would had success with the TECs that I had.

 

Without the cold finger I had no way to get that small cooling power effectively to the camera sensor.

 

Also, to control condensation, I think it's critical to cool the air around the camera as well, so maybe one tec for the camera and one for the cold box?

Yes, that's what we've found. One advantage of the cold box is that being closed from atmosphere you can dry the air ( silica gel bags inside )  and get almost no condensation concerns. Has to be a perfect seal all round though to be effective. That and a cold finger would be the best package.

I have thought of 'skeletonising' my DSLR, getting stuck in with a dremel and\or removing parts of the plastic body but until I get another cheapish Canon to take over astro duties I'd rather keep this one intact and working.

The ASI 120 does for Ha duties at present when I find time.

[AaronSmall]

Thanks, DTS,  This is pretty awesome.  I too was skeptical about the water-electronics mix, but the construction looks pretty sound.  I'm thinking of adapting this to some other ATM projects.

[dts350z]

 

I'm actually in the middle of working on the optical train (Field Flatterner AND Focal Reducer, which goes where, what spacing) so the grey insulation material that normally seals air flow around the t-ring is in the wrong place.

 

Also you can see that the weight of the insulated camera bag is supported by an aluminum square tube attached to the top dovetail. The Camera "floats" inside the bag so the focuser doesn't have to deal with the weight of the bag or water filled tubes, etc.

[admin]

WHOA!  This is beyond cool... pun intended

[dts350z]

There was more discussion in this thread: http://www.otelescope.com/index.php?/topic/591-maximum-delay-time/ Starting at post #11.

[dts350z]

Some parts I used:

 

Copper Shims (goes in the "cold finger" hole): http://www.amazon.com/gp/product/B00IP1T4O4/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1

Thermal Pad (fills the cold finger hole, on top of the copper shims, providing electrical insulation): https://www.amazon.com/gp/product/B004230RUO/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Water Pumps (I used three): https://www.amazon.com/gp/product/B009X6ADCM/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

Thermal Compound (goes on copper shims and between water blocks and aluminum bracket, etc.): https://www.amazon.com/gp/product/B000OGX5AM/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Temprature Gun: https://www.amazon.com/gp/product/B00CVHIJDK/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

tubing (this is more flexible than the stuff from the hardware store, but easier to kink): https://www.amazon.com/gp/product/B000E62TCC/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Water Blocks: http://www.amazon.com/gp/product/B00IHWAV3E/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Fan: http://www.amazon.com/gp/product/B0026ZPFDE/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Radiator: https://www.amazon.com/gp/product/B00CFDSB4C/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

insulated lunch bag for camera: https://www.amazon.com/gp/product/B00KHJXK6K/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

Stuff from the hardware store:

 

Tubing Clamps

Tubing connectors

Plastic "El" thingys to keep tubes from kinking

Stiffer tubing (used only inside the camera bag)

flexible pipe insulation (many stores only have stiff stuff, I got the flexible stuff at home depot)

Stickon "gap" insulation (goes around the nose piece, or whatever else is screwed into your Tring, to seal the whole in the camera bag)

Lots of reusable wire ties and velcro

 

I had a piece of plastic, actually a card holder like you see on your table when you go out to eat, That I used with some standoffs to create an air gap between the radiator and the insulated bag. 

 

I also use some wooden dowels to make a lightweight frame inside the insulated bag. 

[dts350z]

The "bracket" that attaches to the camera tripod connection, fills the LCD cavity, and makes the thermal connection from the two water blocks to the "cold finger" hole in the back of the camera, was made for me at a machine shop.

 

I bought a chunk of 1/4 copper, thinking I could bend it myself. Oh my god that thing is a door stop and even the machine shop couldn't bend it! The bracket they made for me is made from 3 pieces of 1/8 aluminum. One L shaped piece and two rectangular pieces that fill the LCD cavity. Bolted together and with thermal paste in between the layers, and between the L bracket and the water blocks.

[s3igell]

Perhaps you can include some of the Performance Figures (Temperatures, Watts Usage, etc), and the Physical Measurements (Size, Weight, etc)...

[dts350z]

By the way, if you do want to bend the copper tubing to wrap around your guide camera (see caution note in post at top of thread) you can do it without kinking by filling the tubing with something that won't compress, like sand or salt. Search on YouTube for bending copper coils.

 

I used ice (fill it with water and freeze overnight) but you only have maybe a minute to bend before the ice starts to melt and you get a kink.

 

Be sure to have a lot of extra tubing to hold onto and bend, and have something really sturdy and fixed in place to bend around. Obviously it needs to be 1.25" dia to match the 1.25" camera.

 

Put a little tension in the opposite bend direction to move the coil from your bend jig to the camera.

[dts350z]

Perhaps you can include some of the Performance Figures (Temperatures, Watts Usage, etc), and the Physical Measurements (Size, Weight, etc)...

 

I covered some of that in the other thread but here goes:

 

In summer, I get about 41 degrees F, as read from the EXIF data. This is for 8 minute subs with dithering. Endless discussion of what, if anything, the canon EXIF temp data actually means, and if it is read at the beginning of the exposure or the end, so that's why I mention the length of the subs and the dithering.

 

In winter I've seen 35 degrees F, with maybe the first sub reading a little lower (lending to the theory that the temp is actually from the begining of the exposure).

 

This is compared temps above 70, without cooling, and depending on how long it's been since you did a live view, which can heat things up to 120 F. The cooler helps speed the post live view cooling to just a minute or two.

 

I use DarkMaster and a library of darks to match things up temp wise. Not sure what I'll do if a switch to CCDStacker from DSS however.

 

 

For watts did you mean for the pumps and fan? I'll measure it when I get home. The energy of 20 lbs of ice melting can be found on the web. IFRC I would need >115 watts of TEC to equal the cooling power, or maybe that was 10 lbs., of ice. I forget.

 

I don't know the weight, but again the focuser only has to hold the camera and the bracket with the water blocks. The bag and tubes are supported from the top dovetail of my scope. The camera "floats" inside the bag.

 

I do know that I was seriously overloaded on my Sirius/HEQ5 mount, with my 8"RC etc.etc., but now I have an HDX110/EQ8 so payload is not a problem. I don't think the water cooling had much to do with the overload problem, however.

[dts350z]

I put a TemPerHum inside the camera bag to plot the attached curves. I only had 10 lbs. of ice, I think dumping that into the large amount of water left from the previous night (vs. the normal 20 lbs.) slowed things down. I took occasional 60 sec exposures until it got down to ~44 F CameraTemp, then a couple of 8 min exposures (my usual sub exposure) to demonstrate the temperature is pretty steady, then went on to do some imaging.

 

I not that the the resolution of the CameraTemp value seems to be 1 degree C, which is what I attribute the final Camera Temp point being so close to the temp inside the bag to.

[dts350z]

Pumps and fan consume 17 Watts.

 

1.32 Amps @ 12.8 Volts

[WORMSS]

I apologise if you state this, but couldn't tell if you are running a closed loop for the transfer or pumping the water directly from the big tub so I am I am not sure what it would do to the pump, but.....

 

Putting salt on the ice would change the melting point and allow it to stay in a liquid state and lower temperatures. This would hopefully (depending on the structure of your original ice) lower the surface area to just the TOP of the water rather than all the little nooks and crannies when having blocks of ice keeping it cooler for longer.

 

If you are running a closed loop this will also increase the surface area to the cooling element.

 

- Colin.

[dts350z]

Open loop.

 

For putting salt in the water or using dry ice I would probably go closed loop and use CPU cooler fluid in the loop (which I bought but haven't used), however I am happy with the amount of noise reduction I am getting at 37 to 41 degrees F so have stopped experimenting, for the moment anyway.

 

Thanks for the suggestion though.