DIY ASI174MM TEC Cooling

[jonathan_]

I recently purchased a ZWO ASI174MM and was interested in how it would perform for capturing DSOs with some cooling, as it has a reasonably sized sensor. For the TEC module I used a 40mm x 40mm TEC-12706 as I had a few of these from a previous project already. The back of the camera has some almost conviniently placed M4 threaded holes for mounting, unfortunately the spacing is 39mm, meaning I had to rotate the TEC to fit it. For heatsink compatibility I went for 75mm spaced holes to allow mounting of theoretically any Intel socket 115x compatible CPU coolers.

A few minutes in sketchup and I came up with a design for a bracket.

I used the only bit of scrap metal I had at a suitable size, which happened to be be 0.9mm copper sheet. I only had hand tools available to use so the end result wasn't exactly accurate, but plenty good enough. Here is is with the TEC and heatsink installed.

After powering it up and leaving it a while to cool down I was able to compare the noise with and without cooling. These two noise samples were 60s exposures at 200 gain with sensor temps of 44c and 14c, both were from the top left corner of the frame and both stretched by the same amount.

A pretty big difference!

And of course a test M31 shot (in horrible conditions, cloudy/windy), through a TS65Q on a HEQ5 (guided). 15x 60s lights at 100 gain, 7x darks. Sensor temperature was 8.6c for the whole session.

[JamesF]

That's not to be sniffed at!  I know ZWO plan some cooled cameras for the future, but I'm not sure the 174MM is one of them.

James

[JamesF]

It strikes me too that for these cameras getting to a stable single figure temperature in the 5C to 9C range is probably about optimal.  Going too close to freezing is surely going to cause problems with dew and it would probably be quite tricky to deal with as the sensor isn't in a sealed chamber.

James

[michael.h.f.wilkinson]

Very nice indeed. I might well try something like that with my ASI174MM

[Chris]

Good work, the results look pretty clean.

[michael.h.f.wilkinson]

How do you power your Peltier element?

[jonathan_]

How do you power your Peltier element?

At the moment I'm just using a 12v power supply, but I'll probably have to do some sort of temperature control at some point (either by lowering voltage or PWM).

[michael.h.f.wilkinson]

At the moment I'm just using a 12v power supply, but I'll probably have to do some sort of temperature control at some point (either by lowering voltage or PWM).

Thanks! I must have one or two heat sinks somewhere, now all I need is that Peltier element (and some spare metal)

[silios]

Awesome mod Jonathan

[michael.h.f.wilkinson]

I got myself a TEC12706 as well, and dug up a heat sink of a Core-2 Quad. I suppose the latter is big enough (I removed the fan in case it caused vibrations).