Geoptik Cooling box for dslr

[philming]

Hi all !

Is anyone here using this polar box ? What are the results ?

http://www.teleskop-express.de/shop/product_info.php/language/en/products_id/4824

I like to be on site without a computer so I'm wondering how one can align the OTA or frame the shot object with such a device.

Plus is it even possible to shoot near the meridian with such a big box attached ? Doesn't it bump into the tripod or the mount ?

Best regards,

[JamesF]

I think if I were to shell out 200 euros on something like this I'd be wanting to see some typical performance figures first, including temperatures measured from inside the camera where it matters. Gina would have some useful input from her experimentation I'm sure, but I really struggle to persuade myself that it's going to do that good a job of cooling an unmodified camera once the camera starts generating heat. I can see that by starting the cooling off before you want to begin imaging it might be possible to reduce the camera temperature quite a bit, but once the camera starts generating heat I wonder if the lack of any viable circulation mechanism for the cold air or physical path for heat transfer out of the camera is going to mean it doesn't actually make that much of a difference.

James

[philming]

Well, if you shoot in the summer heat, and get the surrounding temperature 20 or 25° below, the signal - noise ratio MUST get better...

I compared the first (11PM) and last (2h30AM) shots I have done during a same session, and the noise level difference between the two is impressive.

Si I guess lowering the surrounding temperature MUST have its benefits...

[JamesF]

Are you cooling the camera at the moment then? Or are you saying that the noise level at the end of the imaging run is significantly higher than at the start?

James

[philming]

No I'm not using the device yet. I'm comparing the two shots of a same session. At 11PM, the temperature is way higher than at 2AM. Thus the difference in voice level...

[Gina]

It certainly helps to give the camera a low ambient temperature but you have to get really low as the generated heat will raise the sensor temperature by 10C above ambienty in a session of a couple of hours. I tried a cooling box myself and got sensor temperature down to around 10C when it merrily went up to 30C without cooling when taking long exsposures. So whole camera cooling does help, particularly in the summer. Every 7C rise in temperature doubles the noise. I'll see if I can find my info and data on whole camera cooling.

I have gone to extreme modding on my cameras to cool the sensor directly and have achieved -15C on long exposures with ambient of 15C or so. But my modding is definitely extreme and could result in a duff camera if great care is not taken. Indeed I did manage to destroy the first camera I tried this on - I stripped down the camera too far I think. This is certainly not something for the faint-hearted or those with little experience of fine electronics. And I'm a bit of a nutter really

My cooling efforts and results can be found in the "DIY - Astronomer" forum.

[AndyUK]

Hi Phil - I think Carastro had (has?) one of these... I had a look at it myself (before opting to go down the CCD route) - Unfortunately it wouldn't fit my 40D without significant modding... and as Gina's noted, the surgery required to insert a "peltier finger" is VERY scary indeed (well it was for me anyway - It's my only DSLR!)

[nmoushon]

To me that box looks extremely easy to make your self for half the cost. I can see plainly that the box is not properly insulated to begin with. All the corners are giant open areas for heat transfer. So flawed there. The fans looks straight from a computer hardware store. Nothing special there. Not saying they don't do the job but just don't look like they add up to the 200Euros cost. The LCD temp gauge doesn't look anything special either. So I would say try and see if you could make one yourself and see what it costs before shelling out that kind of money. I know over here in the US from spare parts laying around and buying used parts I could probably make that for no more than $150. At the most. So thats like what...100Euros ish. The electronic part is pretty basic as well. Could prob find DIY videos on youtube or such as to how to make all the connects. Theres only like 4-5 connections needed to. Not hard at all. Plus you could mod it to your liking.

[philming]

I actually just got one second hand. Along with a Ha EOS Clip for the canon, so both for 170€. Quiet a good bargain I guess.

I just have to adjust balancing issues now. I had to add a little counterweight ahead of my GSORC8 to get the balance point ON the dovetail. Attachment of the RC8 was already at the far end of the dovetail, so with this box added... Now I need an extra counterweight on the CW bar side also...

The other problem I encounter is the cabling. I use an external battery, a Lacerta Mgen that routes a cable to the camera as well, and the USB cable to reach the computer. It's necessary to be able to focus or frame. Big bummer cause I was really proud and happy NOT to have the computer on location. But well, so I got Backyard EOS and it seems to be rather good for focusing and such.

Anyway, I think I'll have to digg a little into the box to get the connectors not breaking after a while...

[The Sailor]

I have been playing around with constructing a cool box for my Canon and this box has given me a couple of ideas, I have to say that I would not pay that amount for it, I am sure they items that make up the box could be got for less than half the price. I don't want to go down the road of cool fingers just yet, stripping the body off is as far as I will go, spare camera anyway . The problem I see is the size of the box, that swinging round the observatory would give me a headache worrying about it crashing, no remoting till I see it's full "orbit" .

Jim