1100D Set-Point Cooling with Peltier TEC and Air Cooling - v3

[Gina]

Due to inadequacies in version 2 of my set-point cooling for my 1100D DSLR I am now looking at a change of design and this will be version 3. Since this is a complete redesign of the mechanics of the camera box and cooling system I decided it warranted a new thread of its own. Details of version 2 are in my other 1100D cooling thread :- http://stargazerslounge.com/topic/157627-air-cooled-tec-with-cold-finger-dslr-cooling/page__st__540

The reason for needing a new version is that the current design permits too much flexure between the cooler and the camera and hence between the Peltier TEC and the cold finger and image sensor. I need to go back to the method used in Version 1 for attaching the cooler to the camera. This needs to be very rigid to maintain good thermal condiuctivity between image sensor and cold finger and between cold finger and Peltier TEC.

[JAS]

I will be following your progress with this Gina, I am interested to see what you will come up with this time round.

Good luck

Jason.

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[Gina]

Thanks Jason

I need yet another different box - the current one is too deep. I need to attach the cooler to the camera and I'm thinking about a smaller/lighter cooler. The current cooling system can attain 28C below ambient which is more than really needed except in summer when the hours of darkness are limited anyway and then again we only rarely get heat waves! I'm thinking of ordering several cheap CPU coolers from ebay - you can't really tell just what they're like from the pics on line.

If the weight of the cooler is taken directly by the camera, the box needn't be particularly strong - it's main purpose will be to maintain a dry atmosphere to prevent dew or frost. Unless other sizes of boxes have become available, I think I shall have to make my own. It would be good to keep the weight down as much as possible. Another necessary property of the box is that it is light tight - don't want stray light getting to the sensor. This is perticularly crucial having enabled extra long exposures by reducing the noise.

So... changes envisaged for V3 :-

1. Smaller and lighter box . Completely opaque.
   
2. Lghter cooler.
   
3. Cold finger
   

[JAS]

How about a box made to size in aluminum? I am a sheet metal fabricator, I could get you a price after Christmas if you draw up what you require?

Jason.

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[Gina]

How about a box made to size in aluminum? I am a sheet metal fabricator, I could get you a price after Christmas if you draw up what you require?

Jason.

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Yes, that is what I was thinking of though I was thinking of making it myself. However, I could work out the size and let you quote me a price - thank you Worth a go.

[JAS]

No problem Gina,

you could have the box tig welded to seal it if you like, we also use press in threaded inserts, studs, nuts and standoffs. Somthing to concider while designing your box.

Jason.

[Gina]

Thanks Jason

I think I may have found a black ABS box that's just big enough to take the camera. I just need to save a millimetre from the top which I think I can do. Internal dimensions :- 145 x 95 x 57.5mm

[RAC]

I made my box out of sign board with 2mm alloy plate for the front and back.

There is a cut out at the back for the peltier so its got constant pressure on the sensor.

[RAC]

Here's a pic

Current imaging rig by meg rac, on Flickr

[Gina]

Nice box, but do you find the elastic bands sufficiend to hold the weight of the cooler when the scope slews?

[RAC]

Ive done many hours with those rubber bands.

[Gina]

Great

How low a sensor temperature can you achieve? Your cooler is a bit smaller than mine and I think I could manage with a smaller one.

[Gina]

I have found I can save quite a lot on the height of the camera without stopping it from working So I will be able to fit it in the ABS box I already have (as long as I can find where I put the lid ).

[Ags]

Good luck!

[Gina]

Good luck!

Thanks Agnes

[Gina]

Camera fits in box fine Now have the camera in bits again to change the cold finger. I'll take some photos shortly.

[RAC]

It'll do -10 when it's 20 outside but I set it at -3. It's got a smaller heatsink on it now to get the weight down even more. I use no few control for the sensor or camera apart from my sensor heater and its never frozen over or dewed up. It all works very well. I did my 8 hour Orion shot with this camera. That shot has no darks or calibration frames apart from flats.

[Gina]

It'll do -10 when it's 20 outside but I set it at -3. It's got a smaller heatsink on it now to get the weight down even more. I use no few control for the sensor or camera apart from my sensor heater and its never frozen over or dewed up. It all works very well. I did my 8 hour Orion shot with this camera. That shot has no darks or calibration frames apart from flats.

That's fine I had a feeling your setup did pretty well

[Gina]

Apart from yet more butchery of my poor camera, I've now stripped all the bits off the old box I'll wait until I get the selection of coolers I've ordered before building everything into the new box.

I won't be without imaging facilities if/when the clouds should part one fine night - I've got two 1100Ds set up for widefield (two if doing WF NB or one as an OSC camera) plus the 314L+ and EFW2 plus Ha and OIII filters for standard NB.

[Gina]

One of the coolers came this morning but it's bigger than I thought - and heavier - oh well, can always bung it on one of my towers.

Happy Christmas everyone

[Gina]

Here are a couple of photos. Cold finger has been replaced and Peltier TEC placed temporarily on top. The temperature and humidity sensor circuit can also be seen together with connector for this and camera power.

1. Top section of the camera has been cut away and unwanted parts removed.
   
2. Camera fitted in the box
   

[squeaky]

Happy Christmas to you too

[Gina]

Happy Christmas to you too

Thank you

[dp297]

Suppose I want to use a 60W system for cooling (and basically my limitation is that I want a 5amp consumption)..........would there be considerable gain in getting an air-cooled 60W system or a 60W liquid cooled system.

I am mainly interested in mobile astrophotography anf for long exposures.

[Gina]

You won't need anything like a 60W cooling system. I'm running a 37W max system and I can get a delta T of -28C with my air cooled system. I gave up on water cooling as it wasn't necessary and I found air cooling quite sufficient and water cooling was inconvenient.