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Super cooled DSLR's


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Anyone on here got a Centralds astro modified camera?

Cooled DSLR Astro DSLR

It seems £700 to modify and super cool your camera is a cheaper alternative to selling and buying a Colour Atik 383L+

OK, the ATIK is bespoke for astro work but you cant focus it without a PC, its doesn't easily take your EOS lenses, it doesn't have its own power supply and hasn't got compact flash storage if you need it, in fact there is a lot it hasn't got to match a modified EOS.

Colour CCD's seem popular in the States but not here in the UK.. is this purely a light pollution reason?

Has anyone any thoughts?

Guy..

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I tried something similar to this, see here (if you are on UKAI):

1000D Peltier Cooling Mod

It ended up being really, really heavy (a few KG's) and my focuser wasn't even close to being up to it at the time. I ended up just selling it shortly afterwards and getting a QHY8 (what I should have done in the first place). I never gave it a proper field test, but the one thing that made me really worry was the amount of moisture that would build up inside the unit

Also having seen what moisture from the sea would do to my QHY8 and waste whole nights because of fogging before I started to dry it out regularly, I wouldn't touch these mods with a bargepole

If you have balls of steel and not a lot of moisture where you are, then feel free :D

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I use dry ice with my Canon DSLR. Works a treat. I have made a polysterene box (much like the G Honis one) but use a small dry ice compartment (seperate from the camera) to cool the space that the camera is in. It seems to cool the camera to about -20oC for about 4 hours with about a mug and a half of dry ice pellets (I can't think of a better measurement unit! :D ) I previously made a peltier unit, but it was just too big a strain on my battery pack....especially when running a laptop, heater bands, camera, etc. The only downfall is you need a supply of dry ice. :D

I've never suffered from moisture...well, the camera has never suffered from moisture. :) You just need to make sure the camera and the compartment that you are cooling is very well sealed from the ambient air. I use sticky backed rubber door seal from B&Q and make sure the various parts are well strapped down to get a good seal. And you need to make sure you can run the camera (battery supply, triggering, downloading) by running wires to the outside...once its all sealed up and the dry ice is loaded...then there's no opening it until the next day.

I use it with standard camera lenses, or with an SCT with a focal reducer. Either way there is only the smallest of air spaces in front of the sensor. And the sensor should be a few degrees warmer that the metalwork around it....so the frost will go there rather than the sensor....at least that's the theory and it seems to work. I would not use it if the sensor was exposed to the whole of the inside of the SCT (i.e. no reducer), or if I were using it on a newtonian.....far too much supply of fresh moist air straight onto the sensor.

But the way I've got it, it does work a treat.

Edited by simon hicks
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Out of curiosity where did you get your dry ice from?

George...I get it as a favour from a very kind friend who has spare from work. But I can't tell you his name!

If you can find someone in the shipping / food / transport / biomedical / R&D sector who's work uses it and has spare...then befriend them quickly!

Otherwise you can buy it from various places on the web. I think they deliver it to your door in slab or pellet form. Alternatively you can buy a dry ice maker...though this looks like a costly alternative.....at which point it might be better to just buy another whopping great leisure battery and go the peltier route. Both routes have their pros and cons.

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Tut, they've just taken my idea and tidied it up a bit :)....and mine was a third the price and still didn't sell! :D

I'd be interested to see a dark frame comparison

post-17826-13387744805_thumb.jpg

Edited by sgazer
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I looked at DI to cool my DSLR, it's great if you can get small quantities of the stuff but a problem to store it if you can only get 10KG at a time.

*** WARNING ***

DI will sublimate at temperatures above -78.5C so it's challenging to store bulk quantities. CO2 is heavier than air and so it'll settle in a layer, if you store it inside you risk death by asphyxiation. If you store it in a (running) domestic freezer, it'll still sublimate and it'll also break your freezer - the refrigerant will freeze at those temperatures and the compressor will fail through lack of lubrication.

The only economical and safe way to store quantities of the stuff is in an old chest freezer that's turned off, completely packed with expanded polystyrene and kept in a well ventilated garage / shed.

I still want to give it a go at some point though :D

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I get about 10kg of pellets at a time in a polystyrene box with walls that are about 2 inches thick. I then place the first polystyrene box inside a bigger home made polystyrene box (Russian dolls!) so the total insulation is about 4 inches all round. This sits in our outhouse that backs onto the kitchen.

I know for a fact that the CO2 gas leaks out and into the kitchen cos it freaks the cat out....it can smell the CO2 and thinks there is a big beast in the outhouse. :D

The 10kg lasts about 8 days stored like this.

I spoon about a kg into a smaller polystyrene box for transporting to the imaging site.

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  • 2 weeks later...

doesn't the cold have a dramatic effect on battery performance? I know it does with NMH but not sure about Lithium cells if thats whats in an EOS battery ...

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Guy,

Yes, the battery will have a shorter life at such cold temperatures, so I use the 12V adapter from Astronomiser. Actually, I mainly use it because I can't get to the battery at all once the cooler box is loaded with dry ice. This seems to have no problem working at those temperatures (well mine doesn't)....though Astronomiser doesn't guarantee it at those temps. But I doubt Canon guaratee their camera works at those temps....but it does.

Cheers

Simon

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