Future TEC implementation

calypsob

I see that the back of the asi120mm is threaded and the description reads, "easy to mount a TEC". Are there plans to produce a ZWO brand TEC for these cameras in the future?

whichwayisnorth

I thought the threads were for attaching a camera tripod. I've been putting my camera on a camera tripod and using it as an all-sky camera a lot recently. I hadn't thought of adding active cooling to it. Now that you mention it I want to do something like that. Time to go through my box of old computer parts and see what I can do.

calypsob

I think it would be a great implementation. I saw an image of the crab nebula taken with one of these earlier and was very impressed, of course I could not autoguide if I was using it for imaging but still pretty cool. I drew up a design today in class which consisted of a 40x40mm copper plate which would be drilled and tapped for a 1/4" aluminum thread which would screw flush with the copper plate. The peltier could be mounted to the top of the copper plate and the whole unit could then screw onto the camera for long exposures. I suppose some JB weld would be needed to lock the thread to the copper plate. Also adhesive pyrolitic graphite would make a great thermal transfer for the bottom of the copper plate which contacts the zwo camera. This way no messy grease or adhesive pads would be necessary to contact the finish of the ZWO camera. Just a thought but I think it could be done for pretty cheap. I think the biggest advantage of a peltier would be that you could sustain a temperature for throughout the night so that the dark frame taken at the beginning could be repeatedly subtracted from the image giving an even amount of dark signal reduction. Not to mention the overall reduction in noise generated from the lower temperatures. Really hope to see a commercial TEC cooler soon.

chripell

Hi,

I was looking into this mod too, but I'm a bit scared about the dew control problem mentioned by Sam in another thread. Do you have any insights about this (or just some pointers to docos explaining the dew creation problems in peltier cooled cameras)? An easier try could be attach a simple fan, like those in PCs, on the copper plate.

robbeh

Hi, here is a thread in a German board regarding my implementation of TEC for the ASI with some pictures. http://www.astrotreff.de/topic.asp?TOPIC_ID=150474&whichpage=1On page 2 there is also my adoption of a desiccant frame, on page 3 another stargazer shows his anti dew construction using 2 resistors.

Recently, I attached another miniature 6x7 mm Peltier directly behind the sensor chip, which gives me faster cooling, slightly lower temp. and half of the power needed to cool the cam (10W vs. 5 W now). I also use a laboratory power source for continous cooling during a night without having to worry about battery power. Additionally I installed heating resistors inside my filter wheel and my secondary mirror to avoid dew problems there. Works very well now.

Robert

chripell

Wunderbar! Thank you very much, with a little help from google translate I'm working through the post. I'll try the first solution, now I'm ordering the peltier cell, I have plenty of old PC fans and stuff lying around.

Sam@ZWO

yes, cooling is interesting, expecially for DSO imging

we may make a cool asi120 in the future.

we just need more testing about this cool mod.

to make sure that cooling won't cause other problems

calypsob

chripell wrote:
Hi,

I was looking into this mod too, but I'm a bit scared about the dew control problem mentioned by Sam in another thread. Do you have any insights about this (or just some pointers to docos explaining the dew creation problems in peltier cooled cameras)? An easier try could be attach a simple fan, like those in PCs, on the copper plate.

You could get some nichrome wire and wrap it around the window to the camera, but it would need insulation and very low heat, it would be really easy to make. Resistors work also, but they take up a lot more space than nichrome wire does. A lot of people that cool their dslr's will glue a thin sliver of nichrome around the outside of their aps-c sensor and heat that with an external power source.

calypsob

Sam wrote:
yes, cooling is interesting, expecially for DSO imging

we may make a cool asi120 in the future.

we just need more testing about this cool mod.

to make sure that cooling won't cause other problems

That is fantastic Sam. I really think if this device were sealed with an o-ring and either argon purged or shipped with a desiccant then you could really control internal moisture very well. As for the cooling source, because the 1/4-20 thread directly contacts the chip I think a screw on peltier unit would be a very excellent upgrade option.