EOS300D megamod progress

[Bassnut (Fred)]

Well, ive got the whole sheebang set up in test mode.

Dual peltier/iced water cooling installed and a 30 min dark taken.

Even with 60w of dual stage peltier and iced water cooling, I found I
could only get the cooling plate to -2 deg (30deg ambient), and the
sensor finger 11 deg at cam entry., I took a dark at 1600 ISO 30 mins,
Unscaled and scaled shown here (amp off).

Progress pics, and darks here.

http://fredsastro.googlepages.com/nebulae

Thermal isolation is a tricky thing, the mounting bracket gets cold
too, but then that cools the whole cam, so its a minor bonus, at the
expense of coolth loss unforch, much to do.

Fred

[iceman (Mike)]

The stretched version has an awful lot of white spots - is that normal?

Exciting watching your progress, Fred. It will be fantastic if it works!

[h0ughy (David)]

Look at the exhaust pipes - wow, is this a v8??. you had a good effort if you took it from 28 degrees ambient to -2 that’s fantastic (30degrees below ambient?), could you post the dark frames so we can have a good squiz at them? And a blow up of a section in both for a good comparison of the noise reduction (do it at iso 1600) then you can compare to mine

[Garyh]

Originally Posted by h0ughy

Look at the exhaust pipes - wow, is this a v8??. you had a good effort if you took it from 28 degrees ambient to -2 that’s fantastic (30degrees below ambient?), could you post the dark frames so we can have a good squiz at them? And a blow up of a section in both for a good comparison of the noise reduction (do it at iso 1600) then you can compare to mine

Now I havn`t seen a modd quiet like that..yeah bit like a supercharged V8 alright... Yeah it would be interesting to compare to Hough`s camera with DF of the same length and iso..

I have been thinking of throwing in a peltier finger onto the back of the sensor like what you have done but I am not very keen on doing it myself..

How thick is the finger and would there be enough room to run a thin insulating layer over the top of it?
Have you had any fogging up/dewing issues with the sensor?

Look forwards to the progression of this interesting project!!
cheers

[Bassnut (Fred)]

Thats an excellent thread you linked to Houghy, I missed that. Ill read up on it, I now realise I need to post the darks in a uniform manner (as the thread discusses) to be able to evaluate the noise reduction. BTW 2 darks are below the cam pics I posted (30min at 1600 ISO).

Mike, yes, noise is apparent, but it needs to be measured properly.

[Bassnut (Fred)]

The finger is only 2mm thick, to allow about a 2mm gap to the PCB above it. I didnt add an insulating layer, perhaps I should, and on the outside plates. Actually, the finger was easier to install than to remove the front lens, less had to be stripped down, and the finger just slotted in under the sensor clips. Unfortunately, thermal transfer to/along the finger is very poor, I need to use much more power. Yes, the external plates were dripping wet and then frosted up, but the finger was OK. When I get it cold enough, ill put the cam in a bag with dessicant.

I used water cooling so I could just cool the water to go lower in temp, a heatsink and fan would not have gone even close to the temp I can get with water, and would have been of a massive size and weight on the cam

The amp off mod was tricky, but works very well, no sign of amp glow at all.