Experiment into peltier cooling my 300d

[Garyh]

Hi all again in the IIS world.....
I thought I would share my experiment into cooling my 300d and to find out if this mod is worth the trouble!!
After seeing Gary Honis and Terrys site to there goes at this mod, I thought I would give it a go myself. Only if we can keep the sensor down to zero in our DSLRs or close to we would have a ccd sensor with noise levels close to the big guns in the astro ccd imagers..

Started with a old coolmaster cpu heatsink (aluminium) as a copper one was too heavy and it was floating around in a box of spare box of computer bits. Purchased a peltier cooler from Jaycar for around $15 drawing about 4 amps at 12 volts and some heatsink adhesive.
To this I glued a plate 40x60mm x 5mm thick as the cooling element which covers half the cameras base connecting to the tripod socket mount.
The other side the heatsink with a 4000 rpm fan mounted on little rubber pads to stop vibration. Exposed areas on the cooling plate were covered in insulating rubber. a rca plug was screwed to the side for quick and easy connecting to 12v battery.
Next I made a insulating inclosure for the camera out of waterproof foam 6mm thick. Cut little access windows to get at the major controls etc with flaps that velcrose up to help keep the heat out as well as condensation.

Attached are some pics of the camera, cooler and enclosure.
Next: Test time: does it work?

[Garyh]

Test Time:

Fingers crossed for the first test...... I was hoping to cool things down by at least 10 c .
I thought I would go at least 10min to see if I could see any difference with my first test. I let the peltier run for about 30min while the camera was powered up to reach a stable temp.
Heres a pic with a comparision before and after at 18 c ambient. Picture is a crop of 400p x 400p in the centre of the image with contrast and brightness stretched in Ps to make it easier to see..
After the experiment I removed the camera from it enclosure just to feel if it felt colder which it didn`t but the metal lense mount felt much cooler, showing that the metal frame was getting nice and cool....

Here it is:

[Garyh]

Second Test:
For a second test I did 2 shorter exposures of 4 min at iso 800 to see the diference. First crop was from a cool night where the ambient temp was below 8 c and the telescope/camera felt quiet cold to the touch. The second frame was taken the night after which was much warmer (about 13 c) but with the peltier running for a hour or so.
Picture has been stretched by 100% in contrast and brightness by 20% to make it easier to show.
After the peltier run there was some ice on the bottom of the camera and a bit of condensation..
heres the picture of the results:

[Garyh]

My conclusion?
After some more experimentation my conclusion is that it does help in the warmer weather and with the longer exposures.
With the 600 second exposure there is quiet a difference with the noise level! but less so with shorter exposures and cooler nights. But with the second test the sensor was cooler than when used without on a cooler night. As a guess I am bringing the ccd sensor down by about 8 degrees maybe a bit more? I was hoping for a better results but that would only be achieved by modding the camera to get the cooling element in contact with the back of the sensor?

Conclusion: ....for warm nights above 20c and long exposures.
.... lower temps not enough difference to bother to set up.
Fan caused no detectable problems at 850mm focal length.
Cost only $30 total and no modding the camera!
I need a way to attach to a tripod with peltier fitted for piggyback shots?

Also had to alter my insulating case as there was some air blowing in from the fan causing a bit of condensation on the bottom of the camera (humidity was rather high)...now fixed.


Any comments welcome or a alterations perhaps?
Cheers Gary...

[Lee]

I think the results look good.... certainly is less noise. How about some pics???

[Garyh]

Thanks Lee for the comment...I have taken a bunch of pics with the peltier on for the whole session and it does help alot, but I havn`t taken any before and after lights as yet of the same subject to directly compare the (lights)..
Seems to be a drought here on clear skies...:-(
Managed some last night but just done some piggyback stuff as I looked for the odd geminid meteorite!!!!
I shall update with a few pics soon I hope!!
Cheers Gary