Cooling a camera - Could you do this?

[PembrokeSteve]

Hi,
I have been thinking of purchasing a ZWOASI178MC camera and noticed there is a more expensive version (a cooled version) also available.
I read the review of the ZWOASI178MC (Cool version) and it got me thinking, can a non cool version camera be "cooled down" before an imaging session,
simply by wrapping it up in an airtight polythene bag and putting it in the fridge?
Could you also do this with a DSLR Body (minus it's battery of course)?
I feel a bit daft coming up with this query, especially if it is a total NO NO.
I am sure I read somewhere that this can work in reducing noise.
Regards,
Steve

[LightBucket]

You could do that, but it would soon warm up to ambient temp, and above,  as the sensor gets very warm when in use, so a waste of time really, it needs to be constantly cooled while in use, if it was that simple  it would make a mockery of the cooled version cameras....

[LightBucket]

Oh and yes the whole point of a cooled camera is to reduce image noise....which gets worse the warmer the sensor gets...

[Adam J]

It would warm up too fast you might get ten mins of imaging by doing this. But most of that would be lost in attaching it and focusing it. You can build diy coolers though. 

 

[MarsG76]

Unfortunately everything written above is accurate, it has to be active cooling.. that said have a look and the cooling project I done on a IS41au02 CCD. The cooling was very effective.. and the results were also very impressive. Basically a 10 minute exposure without cooling was mostly noise and with the cooling running the noise was virtually non existent.

 

 

 

 

[Tim]

Sensor temperatures rise quickly when working, and they cool quickly too with active cooling.

The cooling is worth the extra £££, but dont be too swayed by figures like -40° below ambient. As long as you can cool to -5 or -10 or so you can probably maintain that temperature range for most of the year, and from my limited tests on a cmos cooled camera, working at 0° produced similar images to those at -20°.

Fast cooling can introduce dew or ice on the sensor sometimes, so any homespun job would need to use a sealed chamber and desiccant  measures.

[michael.h.f.wilkinson]

I agree with the above comments. Cooling is really only necessary at longer exposures, so if you use a camera for planetary imaging, the benefit will be limited, because read-out noise is the main issue in that case. In DSO imaging with its long exposure times dark current is the main issue, so cooling is important. I have a Peltier cooler and heat sink lying around to make my own cooler for my ASI174MM or ASI178MM should I want to experiment with deep sky imaging with them

[laser_jock99]

I thougt about a 'budget' method of cooling DSLR's. You'd need to carefully drill an air hole into the inside of the camera body via the tripod mounting bush hole. Using a common 1/4" air hose fitting you could then blow DRY , chilled air (or other cold gas), into the camera body. It's important the gas or air is dry to avoid moisture getting into the camera.

As a source of cold air I was thinking of using a bucket of salt/ice mix (the air temp could be close to whatever the ice is maybe -10 deg C), with a coiled copper heat exchanger- the air flow being supplied by a simple aquarium pump. The air would be dried by flowing through a dessicant chamber first.

I got as far as drilling the hole into the camera body but never tried the cooled gas flow yet. It's possible just flow dried nighttime ambient air through a DSLR might cool it enough to reduce noise? I think the CCD can get quite hot so any way of removing heat would help.

[PembrokeSteve]

Hi, 
Many thanks for your excellent advice and feedback.
Regards,
Steve