DSLR Coolbox Build

[Stargazer33]

As I haven't had any sessions for a while I needed something to do with my astronomy before I forgot what it was all about. So, (don't you hate it when people start a sentence with "So"!) having read an article in Astronomy Now about building a Peltier controlled coolbox for a DSLR camera I thought I would give it a go. My main reason for doing this is that I am not too keen on taking my DSLR apart to do the more radical Peltier cooling that some members have done. Yes Gina, I'm looking at you!

My coolbox is slightly upgraded from the one in the article as I have put a copper ribbon cold finger from the Peltier exchange heatsink to around the DSLR body (bottom and back).

The Peltier cooler was purchased off of the internet and came all the way from China in a plastic bag with a bit of bubblewrap around it so needless to say it was damaged when I received it, but nothing I couldn't fix and I wasn't going to send it back for only £8.

The insulation was from an old camping mat that I bought some time ago to make a dew shield from but was too floppy! The box was one of those food storage boxes that locks twice and the copper was 'rescued' from the scrap bin at work!

The power to the DSLR is via the battery hack that can be found in this forum.

After completion I ran a test indoors and recorded the results via APT which give a cmos temperature reading from the RAW file. Room temperature was a steady 23.5 deg C throughout the test. I set up APT to take 100 frames with a 60 second gap between each frame. The first few readings were at 24 deg C, by the time the test ended APT was reporting a cmos temperature of 13 deg C. That's an 11 deg C drop in temperature over the course of the test and a 10.5 degree drop over ambient temperature.

All I need now is a clear night to test it out in the real world.

[michaelmorris]

That looks like a nice, relatively simple set up.  Do you have any comparative dark frames?

I've just picked up a working mini-fridge whilst at my local tip, so my plan is to build a similar set up myself.  Where did you pick up the copper?

Also, which edition of Astronomy Now had the article?

Thanks

[Mick J]

That looks good, a few years ago we did a 'Honis' aluminium box, worked very well but was heavy, I was on my version 2 and version 3 was to be some sort of light insulation board, was to be eh!

Starting with a mini fridge is a good move Michael - all the bits ready to go.

[michael8554]

AN June issue.

I've a feeling that low temperatures are not good for LCD screens, my observatory clock lost some segments last winter.

Michael

[Stargazer33]

Michael; I work for a local company that makes supercooled magnets for MRI scanners and beam guide magnets for the super collider at CERN. A trip to the copper scrap bin supplied the copper ribbon! 

I did wonder about the LCD myself Michael, but as this is my astro-moddified DSLR & I run it through a laptop, it won't be too much of a disaster if I loose some pixels.

[Stargazer33]

I'll post the first and last dark frames when I am next at my PC.

[michaelmorris]

On 12/07/2016 at 01:13, michael8554 said:

AN June issue.

Michael

Thanks

[Davey-T]

I fitted one of these in mine, looks like you've got room, once it holds at about 5 degrees it's cold enough, I think I read somewhere that it didn't need to go any lower.

Dave

http://www.ebay.co.uk/itm/50-110-c-Digital-LED-Thermometer-DC-5-12V-Car-Temperature-Panel-Meter-Gauge-/281737781298?var=580742350070&hash=item4198e16032:g:qEgAAOSwLVZVk6MU

[michael8554]

On 7/13/2016 at 22:45, southerndiver357 said:

I did wonder about the LCD myself Michael, but as this is my astro-moddified DSLR & I run it through a laptop, it won't be too much of a disaster if I loose some pixels.

I don't know how cold your copper strip over the rear screen gets, I was hinting that I only lost a few segments at close to freezing, at minus temperatures you might kill the whole screen, not just a few pixels !!

Michael

[Dave Lloyd]

On 11/07/2016 at 21:16, southerndiver357 said:

So, (don't you hate it when people start a sentence with "So"!)

 

 

Only in answer to a question?. More seriously, it will be interesting to see how the image noise compares to an uncooled DSLR. Might have a go myself.

[Stargazer33]

On 14/07/2016 at 13:31, Davey-T said:

I fitted one of these in mine, looks like you've got room, once it holds at about 5 degrees it's cold enough, I think I read somewhere that it didn't need to go any lower.

Dave

http://www.ebay.co.uk/itm/50-110-c-Digital-LED-Thermometer-DC-5-12V-Car-Temperature-Panel-Meter-Gauge-/281737781298?var=580742350070&hash=item4198e16032:g:qEgAAOSwLVZVk6MU

Thanks Dave, I will look into adding that.

 

On 14/07/2016 at 23:54, michael8554 said:

I don't know how cold your copper strip over the rear screen gets, I was hinting that I only lost a few segments at close to freezing, at minus temperatures you might kill the whole screen, not just a few pixels !!

Michael

Michael, I'm not sure that my coolbox will get down to minus temperatures. Mind you if the 10°C drop is standard and it is only 5°C outside I suppose it could go to minus figures. As the CMOS sensor runs at ~20°C I don't think it will get that low.

If I fit the temperature gauge that Dave has suggested, I may fit it to the cold finger which would tell me how cold that is getting itself compared to the temperature information for the CMOS sensor from the RAW file.

[Gina]

My comprehensive series of tests on cooling the EOS 1100D sensor has shown that no benefit in S/N is derived from cooling below -5°C and only a little below 0°C.  I think other DSLRs are likely to be similar.

[Stargazer33]

Thanks Gina, that's good to know.

Finally I have processed the before and after images for your perusal.

They are both 10% crops of the bottom right hand corner of the original frame. Both have had the brightness pushed all the way to the right in PS11 (CS4). The numerical value is +150 (what ever that stands for?).

 

START OF TEST: CMOS sensor at 24°C

 

END OF TEST: CMOS sensor at 13°C

I think that is pretty conclusive!

[Gina]

Good result

[cjdawson]

hmm.   I thought a DSLR cooler was a bit of a gimmick.  Having seen that I'm thinking again.  This leads me to thinking is it possible to make a DSLR cooler that allows me to still access the back of the camera.  I'm thinking specifically of my Canon 70D, which has a flip out screen, so might be able to get the to go outside the cooler.  Then I'd need some way working the buttons on the back of the camera.   The issue that I'm seeing is that I don't really fancy waiting 30 mins before I start a 3 hour imaging session, as the setup time is already a fairly lengthy process.

[Stargazer33]

On Sunday, July 17, 2016 at 22:44, Gina said:

Good result

Yes, I'm very happy with the result and to be honest a bit surprised that it works! ?

 

11 hours ago, cjdawson said:

hmm.   I thought a DSLR cooler was a bit of a gimmick.  Having seen that I'm thinking again.  This leads me to thinking is it possible to make a DSLR cooler that allows me to still access the back of the camera.  I'm thinking specifically of my Canon 70D, which has a flip out screen, so might be able to get the to go outside the cooler.  Then I'd need some way working the buttons on the back of the camera.   The issue that I'm seeing is that I don't really fancy waiting 30 mins before I start a 3 hour imaging session, as the setup time is already a fairly lengthy process.

Could you not plug the cool box in whilst you are setting up and waiting for your 'scope to cool down?

[cjdawson]

14 hours ago, southerndiver357 said:

Could you not plug the cool box in whilst you are setting up and waiting for your 'scope to cool down?

I could, but then I'd have a cold camera when I'm trying to look at the flip screen and press the various buttons on the camera to get the settings right.  This is an issue in itself as I have Raynaud's phenomenon which makes astronomy even more of an extreme sport for me. Ideally, I'd like to get away from touching the camera at all.  This is something that I'm just starting to look into.     I'm currently looking into options for getting images by using a laptop to remotely trigger the camera.  So far I've found out that nebulosity will run my DSLR and my Meade DSI without any problems, so this might be an alternative route that I could take.

[Gina]

When I was playing with cooled DSLRs I had it remote controlled.

[bluemaxroe]

Sorry if I missed it in the thread.   Did you/can you give an indication of the weight of the heatsink and fan assembly?    Looks like a worthwhile project if my focuser can cope.

[Stargazer33]

Sorry bluemaxroe, we have been busy getting ready for our move. The whole unit weighs just over 1.4 kg. That's peltier cooler unit, copper cold finger, foam insulation, 2.3L Lock&Lock box, USB cable (2m), power cable for peltier and Canon battery hack for mains supply. I'm afraid that I can't weigh the peltier cooler on its own as I don't want to remove it from the box as it was a bit of a devil to get in.

HTH

[Stargazer33]

UPDATE:

I have 'acquired' some thicker copper ribbon (approx 1mm thick) from the works scrap copper bin and a circular 700ml Lock&Lock tub that I am going to turn into a coolbox for my QHY5L IIc camera. I will post pictures up here when I get round to making it but the move will be happening in the next week or so, so it may not be for a while yet!

The last time I looked the cheap peltier coolers from China had disappeared from Ebay.

[david_taurus83]

Sorry to dig up an almost 2 year old topic, but how did you get on with this in the end? Looks like a nice cheap easy solution! With summer months coming up I was wondering if your little cooling box can keep the camera at winter time temps. Are there any vibrations from the fan?