Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Using a Coleman 12V beverage cooler and a small metal Community Coffee canister, I made a peltier cooling system for my Canon 450D (XSi). Some photos posted here:
http://ghonis2.ho8.com/rebelmod450d16.html
Cooling the whole camera is easy with the 450D because of its small size and weight. Since it has one USB cable for all computer control and imaging functions, there is no need to press buttons on the DSLR or view its display. I'll be posting complete construction details along with test results from the cooled camera soon.
Gary Honis
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Gary Honis
DSLR Modification Service
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Andrew Welsh
Carpal Tunnel
Reged: 03/28/06
Posts: 2488
Loc: Rochester, NY
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Let me be the first to say... cool, man. 
Har har.
Thanks for the writeup, I may do this project some day.
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LX200 8" classic, f/10, Meade eq. wedge, .63x FF/FR
Canon 40D and 5DMkII, unmodified
Canon EF 200/2L IS, 300/4L non-IS, 100/2.8 Macro, 50/1.4, 85/1.8, 35L, 24L, 16-35L and Peleng 8mm fisheye
Orion Apex 102mm (4") Mak-Cass
Pimped out with accessories and bling
My DSLR Astrophotography Webpage and photo bucket with full equipment list
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Andy,
Another cool feature is that beer cans still fit in the cooler for those cloudy nights 
Gary
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Gary Honis
DSLR Modification Service
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JerryWise
Postmaster
Reged: 12/26/03
Posts: 7834
Loc: Lexington, SC
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Great job. I'll sure be waiting for your writeup.
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Jerry
Celestron C-11
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waassaabee
Carpal Tunnel
Reged: 11/26/07
Posts: 2710
Loc: Central California Coast
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Gary... That's sick !! I think I have everything to make one too! Well except the Coleman cooler, and the 450D... 
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Gary
34N 120W
-My kingdom for blue squares!-
WO Megrez 90FD/TV 0.8x FR/FF
AT8RC
mini Borg 50/Q-Guide/PHD
CGEM
Canon 350D Hap Griffin Baader mod - o.o
My Friend Flickr
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Nils_Lars
Post Laureate
Reged: 01/04/08
Posts: 3443
Loc: Santa Cruz Mountains , CA
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Thats a cool project , would be nice for those summer nights.
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Erik
Orion Atlas Self Hypertuned (EQMOD)
Orion ED 80
Williams Optics VII reducer
Celestron 8" SCT
Orion Starshoot Autoguider
PHD guide
Canon 400D Hap Griffin Mod w/Baader filter
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Stilleto CVF and Bahtinov mask
Tamron 75-300mm&28-80mm lenses
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http://www.flickr.com/photos/31986095@N05/
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walt r
Post Laureate
Reged: 02/13/07
Posts: 3463
Loc: Doylestown, PA
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Looks good, just the thing for those still hot nights. I would like to see a graph of the dark noise vs. the temperature of your system.
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Walt
Obsession 18" f/4.45 #1370 AN/SC
MK67 Deluxe 6" f/12 Mak-Cass, Super Polaris GEM, JMI MicroMax DSC
DIY 60mm f/6 Achromat
Cookbook 245 CCD
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wrather1
AstroBear
Reged: 10/25/05
Posts: 3880
Loc: Dallas, Texas
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Very cool! 
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"Don't worry about what telescope you own, or its quality. Just get out under the night sky, and enjoy God's wondrous universe." - T. M. Back
Meade RCX400-12 "Ursa Major"
TMB 130SS + EQ6-PRO "Ursus Polaris"
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Ptarmigan
Carpal Tunnel
Reged: 09/23/04
Posts: 2359
Loc: Arctic
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Cool idea.  I like to see the results.
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Ptarmigans=Cute and Cuddly
Meade Starfinder 8
Nikon 10x50
Rebel XT
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Lee Jay
sage
Reged: 02/27/08
Posts: 463
Loc: Westminster, CO
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I've never understood something about cooled sensors/cameras. How come they don't just fog up like crazy and therefore fail to produce images?
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LLEEGE
Running out of Oxygen
Reged: 03/03/05
Posts: 9079
Loc: Cloud-chester,NY
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I would imagine that as long as the sensor is not cooled below the dew point, it shouldn't fog. Cooled CCD's are sealed in an inert gas chamber to prevent fogging. (no moisture to condense.
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"Okay! You draw the straws. I'm-a taking the parachute."
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Mike B.
Carpal Tunnel
Reged: 10/24/05
Posts: 1687
Loc: Louisiana
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Quote:
I've never understood something about cooled sensors/cameras. How come they don't just fog up like crazy and therefore fail to produce images?
I would think the humidity level would dictate whether it fogs up or not. You could put a bag of dessicant inside if it was too high, maybe?
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Clear skies!
Mike B.
My Homepage and Astrophotos
Edited by Mike B. (07/08/08 10:22 PM)
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Thanks for the suggestion, will do. I also thought an animation of the dark frame crops as they improve over time and lower temperature would be good.
I had a chance to test the peltier cooled 450D on my scope tonight. I took 5 minute dark frames every 5 minutes with a 55 second pause between exposures over a three hour period. The results were discouraging. After 30 minutes I only got a 7 degree Fahrenheit drop and after one hour the system leveled out at a 10 degree drop. In comparison, tests with the camera in the orignial cooler gave a 17 degree F drop in 30 minutes and a 23 degree drop at one hour continuing to a leveling out at a 30 degree drop below ambient.
Guess it's back to the drawing board:(
I thought maybe there was conductance from the camera body through the T-ring into the telescope focuser, but I later tested the cooler removed from the telescope and there was no change in cooling.
I'm thinking maybe there is not good conductance between the peltier and the coffee canister? I fine sanded the coffee canister metal and used thermal paste but maybe I used too thick of a layer of thermal paste? Or maybe the conductance of the metal used in the coffee canister is not that good and I need to add some aluminum strips or a heat sink inside the canister? Maybe the R value of the styrofoam cooler I used is too low? Maybe its a combination of the above.
If anyone has advice, please let me know.
Gary
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Gary Honis
DSLR Modification Service
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SuperDuperMan
member
Reged: 04/21/08
Posts: 67
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Hi Gary!
You "fridge" looks very nice. My simple cooling system has not been tested under the stars yet, but initial indoor dark frame results were ok, I think. I did not measure any temperature, only the noise in the dark frame. See this message:
http://www.cloudynights.com/ubbthreads/showflat.php?Cat=&Board=DSLR&Number=2427231&Forum=f85
Best of luck,
Søren
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Kentari
scholastic sledgehammer
Reged: 11/19/06
Posts: 794
Loc: Belgium
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Very nice! I look forward to your writeup. I've been considering building something similar too, but it is't as straightforward with a 20D (no live view etc...). My new 40D will arrive one of these days reducing the number of cables needed to 1... Now I only need a more decent laptop to control it.
Koen
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Darkstar 355 f/5 Dobsonian
Orion UK 8" f/4.5 Newtonian and WO ZS 80 FD on Losmandy GM8
Canon 20D DIY mod with Baader filter
A bunch of lenses: 10-22mm f/3.5-4.5, 17-40mm f/4, 50mm f/1.4, 70-200mm f/2.8, 300mm f/2.8
www.koenvangorp.be
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Søren,
Thanks for the link. Didn't see a photo of your cooler, do you have one? Bert really has created a cooling monster there!
Gary 
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Gary Honis
DSLR Modification Service
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SuperDuperMan
member
Reged: 04/21/08
Posts: 67
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I did not post a picture because it is very similar to this one:
http://www.pbase.com/terrylovejoy/peltier_cooling
I.e. just a plate attached to the camera hole in the camera and the peltier is attached to the plate.
Søren
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Søren,
Very simple system!
I'm getting closer to a solution to my problem. Using two temperature probes, one directly on the cold plate support inside the cannister, and another nearby inside on the canister wall, I found that the cold plate probe gave a temperature drop in ten minutes of 40 degrees F below ambient while the coffee canister dropped only 10 degrees. So now I'm checking if I have a good cold plate to canister connection or if I need to add some aluminum to aid in cooling inside the canister. It's good to know I'm getting that big temperature drop inside the canister. Now I just have to get that cold into the camera. Recorded a 50 degree temperature drop at one point and it warmed my heart.
Gary
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Gary Honis
DSLR Modification Service
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walt r
Post Laureate
Reged: 02/13/07
Posts: 3463
Loc: Doylestown, PA
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I'm thinking that you need to thermally connect the cold plate directly to the camera.
What comes to mind is a silicon pad to contact the rear of the camera body. Silicon pads are used to heat sink electronic devices when thermal grease would cause a problem.
A manufacturer is Berquist. Check DigiKey part number BER165.
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Walt
Obsession 18" f/4.45 #1370 AN/SC
MK67 Deluxe 6" f/12 Mak-Cass, Super Polaris GEM, JMI MicroMax DSC
DIY 60mm f/6 Achromat
Cookbook 245 CCD
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Hi Walt,
The 450D has a plastic body. The rear (back side) of the 450D body is mostly the large display screen. The tripod mount on the bottom does make connection with some metal strips inside the body of the camera. The right side of the 450D is mostly the battery compartment and it is plastic. I know it would be best to directly cool the imaging chip with a peltier, but I thought I would try whole camera cooling, just as if you were imaging on a night with a 40 degree Farenheit ambient temperature. These peltier coolers keep food cold so why not a camera? Over time in the cooler, the camera should adjust to the temperature of the peltier cooled chamber. Resulting dark frames will be the measure of how useful the cooling system is.
Gary
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Gary Honis
DSLR Modification Service
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SuperDuperMan
member
Reged: 04/21/08
Posts: 67
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Hi again.
Did you mount a fan inside the cooling compartment to circulate the cold air? Preferably over or near the cold plate to draw the cold away. I could not see one on your pictures...
Søren
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Qkslvr
Pooh-Bah
Reged: 06/23/06
Posts: 1316
Loc: NE Ohio, US
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I used a cast aluminum project box to mount my spc900 in, and then cool that.
I would think a steel tin wouldn't conduct the cold very well.
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Mike
Onyx 80ED/N8/CG-5/40D
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walt r
Post Laureate
Reged: 02/13/07
Posts: 3463
Loc: Doylestown, PA
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Gary,
It great that you are experimenting as CCD's do have lower noise at lower temperatures, about half for each 7°C lower.
I'm just throwing out ideas that may or may not work.
A few other suggestions also sound good. Like placing a heat sink on the cold plate inside the box with a small fan to circulate the cold air around the camera body or in reality circulating the hot air to the cold plate.
Also don't quickly dismiss plastic as being a thermal insulator, some plastics are fairly good at thermal conductance. Tests are needed to determine the characteristics.
Good luck and keep us posted with your results.
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Walt
Obsession 18" f/4.45 #1370 AN/SC
MK67 Deluxe 6" f/12 Mak-Cass, Super Polaris GEM, JMI MicroMax DSC
DIY 60mm f/6 Achromat
Cookbook 245 CCD
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Walt and Søren,
I'm rebuilding the cooler using the aluminum chamber in the original cooler. I do plan to include two small fans to circulate air. Thanks for the advice.
Mike: The problem seemed to be the coffee canister being steel and not being a good thermal conductor. The revamped cooler is going to be somewhat heavier since I'm using the whole aluminum chamber of the original cooler with just the plastic part sawed off. Should have it done tomorrow for dark frame and temperature testing. I may make another one after this that is a little smaller and lighter to see if I can maintain the same cooling effect.
Gary
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Gary Honis
DSLR Modification Service
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agambaros
member
Reged: 01/04/07
Posts: 38
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Hi to all,
If you cooling DSLR with a box have you see any problem about freezing and create of ice on CMOS, case of DSRL (inside and outsite) TMount, etc?
Is a good idea regulate amount of cooling if the night is very wet?
Thanks
Alessandro
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Thanks for the suggestions. I rebuilt the camera cooler using a part of the original cooler instead of the coffee canister and added some internal fans as you guys recommended. Got almost a 40 degree Fahrenheit drop from an ambient temperature of 77 degrees. Used a desiccant pack inside the cooling chamber and had very little moisture on shutdown after the lid was taken off. Photos of the new version cooler along with temperature and standard deviation graphs and dark frame crops can be seen here:
http://ghonis2.ho8.com/rebelmod450d16b.html
Gary Honis
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Gary Honis
DSLR Modification Service
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agambaros
member
Reged: 01/04/07
Posts: 38
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Thanks Gary for your update.
Why about "Heatsink mounted on aluminum chamber with thermal paste and screw near camera"?
It isn't sufficient only one fan near peltier?
Bye
Alessandro
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Alessandro,
Good question. The blue round fan that is near the peltier is a computer chip heat sink cooler. It comes with a thermal paste adhesive pad and airflow is directed out radially from the fan. I guess it alone may be enough to circulate air within the cooling chamber. As you can see from the pics, I used the whole aluminum chamber from the original cooler and it is larger than needed for the camera so I had some extra room. The second heat sink is one I saved from an old TV and thought that it wouldn't hurt to use another very small fan to blow cooled air through its fins directly onto the back of the camera body. The idea was to speed the rate of cooling of the camera body. I had recommendations after making the first version to add fans in the cooler. I'm learning about peltier devices and thermal cooling as I go, experimenting and am just guessing at what I think might work.
If I make a third version of the cooler, I would try to reduce its size and weight a bit. It would be easier to make smaller, but I'm worried if I reduce the amount of aluminum used in the chamber that the cooling effect will be reduced. Is there a thermal engineer in the house?
Gary
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Gary Honis
DSLR Modification Service
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jcham21
sage
Reged: 12/02/07
Posts: 358
Loc: Tucson, Arizona
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Great work, I enjoyed the graphs and pics on your site. Very informative.
James
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James
Canon XTi
Canon EF 200mm f/2.8L II Camera Lens
Celestar 8
Main Astrophotography Gallery
Comet Lulin Gallery
How To Make a 6" F/15 Refractor
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agambaros
member
Reged: 01/04/07
Posts: 38
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Hi Gary,
have any information about power of your Peltier?
My target plastic box will be 1,5 o 2,0 liter and I've order a Peltier of 45W (40x40mm). Now I should find heat sink with fan for external (for CPU on ebay there is a lot), and a small fan to put inside.
Have you the weight of version I & II & III?
Thanks
Bye
Ale
Edited by agambaros (07/15/08 11:28 AM)
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Ale,
The peltier on my cooler is about 40mm X 60mm. The cooler's DC cord has a 5A fuse so maximum power before fuse blow would be 60 watts. I haven't measured the current draw during cooling.
When you say you will be using a "target plastic box", understand that you will need an ample cold plate inside the box for the peltier cooling to work correctly.
Version 1 of my cooler weighed 1.5 pounds without the camera. Version 2 of the cooler weighs 3 pounds 1 ounce without the camera. There are a few changes that could be made to lighten and reduce the size of the camera a little, but I'll spend time testing the cooler for now.
Good luck with your cooler.
Gary
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Gary Honis
DSLR Modification Service
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SuperDuperMan
member
Reged: 04/21/08
Posts: 67
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Very nice rebuild and website! You seem to also get a constant noise after a while, not the constant increase without cooling. My guess is that this will be very good for dark subtraction, even if the temperature is not lowered significantly like in an astro CCD camera.
Søren
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Ale,
Found the owners manual for the cooler; I guess some people read those:)
In the Specifications: "Amperage draw: 4 Amperes (approx. 48-Watts").
Gary
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Gary Honis
DSLR Modification Service
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Bert
sage
Reged: 02/17/06
Posts: 430
Loc: Australia
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Hi Gary I use two of these Peltiers in my modified fridge to cool my 5DH.
Specs
Measures: 40 x 40 mm with lead wires.
Temperature Differential (DT) (Th=27 degrees C) : >=68 degrees C
Optimum Input Voltage (Vmax) (Th=27 degrees C): 15V
Optimum Input Current (Imax) (Th=27 degrees C):8A
Maximum Cooling Power (Qmax): 68.09W
It is best to run at 75% of max power so for these that would be 12 or 13V at 6 to 7 A. The TEC in your fridge i 40x40mm and is easily replaced but be careful not to crush it by overtightening the screws.
Below is a graph of my cooler with ambient from a warm start. I have ordered a peltier temperature controller that has a microprocessor and has all the bells and whistles to get stable temperature control. Will make darks and lights have exactly the same temperature even with ambient changing.
Bert
Edited by Bert (07/17/08 04:52 AM)
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Bert
sage
Reged: 02/17/06
Posts: 430
Loc: Australia
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Here is a picture of the fridge. I have found the heat pipe CPU coolers are far better than a plain Al heat sink.
Bert
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Bert
sage
Reged: 02/17/06
Posts: 430
Loc: Australia
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And another with roach! The CPU coolers have 40x40mm bases that fit neatly to the TEC's 'hot' side. The expanded foam gives better insulation of the hot side from the cold side.
Bert
Edited by Bert (07/17/08 04:44 AM)
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agambaros
member
Reged: 01/04/07
Posts: 38
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Quote:
....
I have ordered a peltier temperature controller that has a microprocessor and has all the bells and whistles to get stable temperature control...
Hi Bert,
can you write informations about this temperature controller (where,how, what, etc)?
I thinks it's a amazing have fixed-temperature into cooldbox!
Alessandro
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Hi Bert,
Thanks for the info on your cooler. It does seem from your temperature graph that the cooler/camera temp is jumping around a bit so that temperature controller should help.
I did the conversion from Celsius to Fahrenheit and if correct, you are seeing about a solid 40 to 43 degree Fahrenheit temperature drop. With my single stage peliter and original test results, I am getting a 38 degree temperature drop. I don't think a few more degrees of cooling would help much with the dark frames, but maybe the speed of cooling. Have you made any dark frame tests?
Weight isn't a problem with your camera lens imaging setup, but I'm trying to keep weight and size to a minimum for use on a telescope focuser. I've looked into die-cast aluminum alloy project box enclosures but they are heavy and have low thermal conductivity. I may try some thin AA 2024 sheet aluminum with high thermal conductivity and fashion a box to snugly fit the camera and insulate with styro for the next version. I'm not a metal worker so this may be a challenge for me. Another option is to rework the aluminum shell of the original cooler to a smaller size to fit just the camera and a small fan and then add styro.
Gary
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Gary Honis
DSLR Modification Service
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Bert
sage
Reged: 02/17/06
Posts: 430
Loc: Australia
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Alessandro here are the controllers. I decided to get the first TC-48-20 as it has some very useful features.
http://www.tetech.com/Temperature-Controllers.html
Bert
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agambaros
member
Reged: 01/04/07
Posts: 38
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Quote:
Alessandro here are the controllers. I decided to get the first TC-48-20 as it has some very useful features.
http://www.tetech.com/Temperature-Controllers.html
Bert
Very very nice but at the end my attention go to the price... 
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Freddy WILLEMS
Carpal Tunnel
Reged: 11/13/05
Posts: 2557
Loc: Hawaii, Honolulu
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I was following this forum, and forgive me for reading NOT all the details.
At the moment I'm rebuilding my C 14" with internal cooling fans and outside Peltier coolers and fans and heat sinks.
Just have a few Peltiers left over and want to build a Canon 10D cooling system aswell,
Just want to know were the peltier cooler touches the camare body ? I guess the botton part with the metal for the tripod holder will be the best place. (?) Did anybody experiment with that before ?
Please do let me know your opinions...
Freddy
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Freddy
Meade 14" LX200 GPS UHTC GPS on permanent pier
Celestron C 14" Peltier cooled for planetary imaging.
Meade 10" LX200 & TITAN 50:1 mount Gemini 'go to'
Meade 127 mm f/9 APO & TITAN 50:1 mount Gemini 'go to'
W/O 102 mm f/7 APO doublet
Orion 80 mm f/7 ED
DFK 21AU04.AS
ToUcam 840 II pro
Canon 10D Unmoddified
Canon 40D Hutech moddified
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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I completed Version III of the peliter cooler for
the Canon 450D and posted pics and test results here:
http://ghonis2.ho8.com/rebelmod450d16c.html
For this third design, I was focused on getting the cooler as small and light as possible using the peltier/fan device from the peltier beverage cooler. I built the aluminum cooling chamber out of very thin sheet aluminum of a size that just fits the 450D camera and a small circulating fan/heatsink. Used a pop rivet gun and some JB Weld epoxy to hold the aluminum chamber together. I'm getting a 44 degree Fahrenheit temperature drop and the dark frames look great. Hope to get some long exposure deep sky images soon.
Gary
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Gary Honis
DSLR Modification Service
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SuperDuperMan
member
Reged: 04/21/08
Posts: 67
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Quote:
I guess the botton part with the metal for the tripod holder will be the best place. (?) Did anybody experiment with that before ?
Yes:
http://www.pbase.com/terrylovejoy/peltier_cooling
http://picasaweb.google.com/masterOfTheUniverse2008/AstroTests/photo#5205895529869117266
Søren
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TheSheriff
sage
Reged: 07/15/07
Posts: 237
Loc: Oregon
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Now that looks to be a very efficient design...good job!
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Brad
C8SE XLT, TMB 80SS, Orion ST-80
Atlas EQ-G/EQMOD
40D (Self-Mod), WO 0.8 Flat II, SSAG
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walt r
Post Laureate
Reged: 02/13/07
Posts: 3463
Loc: Doylestown, PA
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Great job Gary and thanks for sharing. That is a slick implementation.
On the SD curve of the Darks, I'd guess the initial rise is due to the camera electronics warming up before the TE's cold penetrates the camera body. That would then be the True lag of the system.
Now for a temperature controller..........
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Walt
Obsession 18" f/4.45 #1370 AN/SC
MK67 Deluxe 6" f/12 Mak-Cass, Super Polaris GEM, JMI MicroMax DSC
DIY 60mm f/6 Achromat
Cookbook 245 CCD
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Bert
sage
Reged: 02/17/06
Posts: 430
Loc: Australia
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That looks very promising as a light design Gary. I received the Peltier controller a few days ago and it works really well.
Set up the fridge with the Peltier controller inside the house with the doors open so ambient was at about 12C. I then shut the doors at 20 minutes on the graph and turned on the house heater. The controller sensor is mounted on the Peltier coldplate inside the fridge. Then plotted the results. As you can see a ten degree C rise in ambient resulted in a rise of only 0.3 degrees C in the fridge air temperature. The 'set' temperature -10.0 C actually only fluctuated from -9.9 C to -10.1 C over the ten degree ambient rise in temperature.
I have not optimised the settings for integral and differential yet I just went with the default.
Bert
Edited by Bert (07/26/08 08:02 AM)
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Bert
sage
Reged: 02/17/06
Posts: 430
Loc: Australia
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Here is a pic of the setup.
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Walt,
Yes, I think that is the system lag. What I need to do is take the same series of 5 minute exposures with the 450D outside of the cooler and plot the results on the same SD curve. It would show the true effect of the cooler on noise.
Based on the SD curve, what I plan to do is turn the cooler on, with the camera turned off, before an imaging session, maybe for a half-hour to an hour. Since the peltier is DC powered, one could always pre-cool the camera from the car's 12V DC on the way to a dark sky site.
Gary
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Gary Honis
DSLR Modification Service
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Congratulations Bert....you have good temp control there. Look out SBIG:)
Another option to a commercial controller is to build one yourself. A standard auto dew heater circuit should do the trick with the power being contolled to the peltier instead of a dew heater. My friend has a circuit diagram here:
http://www.starrynights.us/Articles/Dew.htm
Gary
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Gary Honis
DSLR Modification Service
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walt r
Post Laureate
Reged: 02/13/07
Posts: 3463
Loc: Doylestown, PA
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Quote:
Based on the SD curve, what I plan to do is turn the cooler on, with the camera turned off, before an imaging session, maybe for a half-hour to an hour. Since the peltier is DC powered, one could always pre-cool the camera from the car's 12V DC on the way to a dark sky site.
Gary
That's a good idea. Something else you may need to deal with is frosting of your camera and sensor. If your cooling chamber is relatively sealed then any moisture should freeze out of the air onto the peltier 'heat sink' and prevent frost on the camera. But if you open the box after the camera is cold then it will dew and frost.
I built and still use the Cookbook camera. That design uses a cold finger that freezes out the moisture before the sensor reaches freezing.
--------------------
Walt
Obsession 18" f/4.45 #1370 AN/SC
MK67 Deluxe 6" f/12 Mak-Cass, Super Polaris GEM, JMI MicroMax DSC
DIY 60mm f/6 Achromat
Cookbook 245 CCD
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Bert
sage
Reged: 02/17/06
Posts: 430
Loc: Australia
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Gary pulse width modulation is the way to go as Peltiers do not take kindly to thermostat on and off type regulation. They will fail quickly if controlled this way due to the mechanical stresses set up in what is an easily fractured brittle semiconductor. It was never my intention to hijack your thread only to help as I have already made all the mistakes.
I have been using in camera noise reduction (ICNR) which beats ANY method as the temperature of the dark is close to the temperature of the light. By accurately controlling camera temperature then the darks will match the lights and when ambient is rapidly changing should be better than ICNR. I now can also collect twice the data and have very good dark subtraction.
Here is one of my images a mosaic of the LMC 4MB
http://members.optusnet.com.au/~fmlee/lmcmos_hdr.jpg
Bert
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Bert,
Thanks for your advice.
Peltiers can be controlled safely using the simple on/off method. It depends on the application and if the load is active or passive. If you look at the temperature drop curve of the peltier cooler I built, you will see that the temperature drops to a stable (steady state) cooling temperature. With my cooler, I have not had to turn off the peltier yet even once over a three hour period. With the Canon DSLRs, I don't think the temperature difference of just a few degrees Fahrenheit makes a difference with dark frame subtraction.
Your cooling system however is cycling and in need of some type of temperature control. In an application where the controller will cycle on/off over a period of several minutes, a simple on/off peltier controller is quite appropriate. For systems that need to be cycled on/off in a matter of seconds, a PWM controller should be used. I think that even a low cost ($30) commercially available on/off peltier controller would have worked well for your system, but maybe not with the degree of temperature stabilization you are getting with the ($284) PWM unit.
With the PWM controller are you controlling both peltiers with the unit? My single peltier is providing nearly the same temperature drop as your two peltier cooler and we are using the exact same beverage cooler-peltier.
The mosaic of LMC you posted seems very noisy. What DSLR are you using and can you provide image details such as ISO and length of exposure?
Gary
--------------------
Gary Honis
DSLR Modification Service
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Bert
sage
Reged: 02/17/06
Posts: 430
Loc: Australia
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Details of image Gary.
Details
Canon 5DH, Canon 300mm F2.8L at f/2.8, Hutech LPS filter, all at an ISO of 500.
exposures 2X(5x(30s, 1, 2 min), 10x4 min, 5x8M).Two fields.
Converted to tiff from raw with IP, stacked aligned with RegiStar, LDR produced with EasyHDR. FOV is 7.7x10.8 degrees.
That is not noise it is very dim stars.
Here is an HDR image of the Lagoon and Trifid taken with the 5DH and a 100ED at a FL of 680mm with a FR/FF with the fridge at -12C. 1.6MB
http://members.optusnet.com.au/~trlee8/col+ha+o3.jpg
Even a one degree C difference between dark and light is enough to leave residual noise with the Canon 5DH. Melbourne has the sort of weather that over night the temperature can drop by as much as 10 to 15C even in summer.
Why every degree counts is to give enough head room so that the controlled temperature remains constant over an imaging run (night). At the moment it is winter and last night the temp went from 14C to a minimum of 1C. In summer it can fall from 24C to 8C. This of course happens on clear nights when imaging is possible.
The first graph showed how fridge temperature followed ambient with full constant power to the Peltiers 13V and 12A.
Bert
Edited by Bert (07/27/08 06:04 PM)
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agambaros
member
Reged: 01/04/07
Posts: 38
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Hi Gary,
today I've received Peltier from HK.
Now I'm finding Fan and Heatsink.
Your internal blue model it's very pretty because it's very compact. What is manufacture and if possible the models, please?
Thanks
Ale
Edited by agambaros (07/29/08 01:20 PM)
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Ale,
I got the small blue heatsink/fan from a local computer store for $15. The manufacturer has the specifications and sells it directly online here (long link):
http://www.startech.com/item/FANCSORB-ChipsetVideo-Card-Round-Orb-Heatsink-Fan.aspx
It fits the cooler well as you can see in the attached photo. It comes with a square peal-off thermal sticky pad for attaching it to the peltier metal support plate without the need for screws. I added a little thermal paste around the square thermal pad to help with heat transfer.
Gary
--------------------
Gary Honis
DSLR Modification Service
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agambaros
member
Reged: 01/04/07
Posts: 38
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Thanks Gary.
The manufactor is "STARTECH": very right for our hobby
;-)
I'm reading tecnical specification:
Fan Dimensions
Inches 1.97 x 1.97 x 0.59
Millimeters 50 x 50 x 15
Heatsink Dimensions
Inches 2.17 x 0.79
Millimeters 55 x 20
So total height is only 20 mm: very compact!
I find it on ebay and on other web site.
For Italy cost of this item it's low (9 $) but shipping it's very hight (30$): sight....
Very thanks
Alessandro
Edited by agambaros (07/31/08 11:44 AM)
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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I added to my web site, three pages that detail the assembly procedure for building Version III of the whole DSLR camera peltier cooler I made for the Canon 450D:
http://ghonis2.ho8.com/rebelmod450d16d.html
Gary
Edited by Gary Honis (08/03/08 09:59 PM)
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Bert
sage
Reged: 02/17/06
Posts: 430
Loc: Australia
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Looking very good Gary. Informative how to as well. Be interesting to see how it goes in the field doing some astro imaging.
Bert
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Bert,
Had a short window between clouds and Moonrise on Monday and was able to take first light exposures with the peltier cooled 450D. Imaged the Veil Nebula from my backyard deck and posted the result here:
http://www.ghonis2.ho8.com/082508modXSi.html
Cooling system worked well. Had no condensation or dew. I used small desiccant packs along with a humidity indicator card inside the sealed chamber. Had a 40 degree Fahrenheit temperature drop on this warm summer night and the camera was imaging at below freezing for very low noise at ISO 1600. Star images were not affected by the two fans used in the cooling system.
Gary Honis
--------------------
Gary Honis
DSLR Modification Service
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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As an update, imaged with the cooled 450D at the Black Forest Star Party and had a problem with the front lens of the focal reducer fogging up, as some here suggested might happen. Humidity was high and we had much dew. I had to remove the camera a few times and clear up the fogging with a hair dryer. Will need to come up with a fix to avoid the fogging. Pics of M33 and the Bubble Nebula posted here:
http://ghonis2.ho8.com/090408modXSi.html
Gary Honis
--------------------
Gary Honis
DSLR Modification Service
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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The fogging problem has been fixed. Got out last weekend and cooled the camera down to 5 degrees Fahrenheit for both nights. Took six-minute exposures at ISO 1600 and imaged the Horsehead, Heart, NGC253, 7331 & Double Cluster. Images posted here:
http://www.ghonis2.ho8.com/100308modXSi.html
The dark frames at six minutes were velvet black. Here are some image pixels standard deviation figures of dark frames to give an idea of how cooling improves noise:
Temp_________Exposure____Standard
Fahrenheit___Length______Deviation
77___________5 min_______2602
50___________5 min_______2114
34___________5 min_______1080
05___________6 min_______ 146
To avoid fogging of the front lens of the focal reducer, I used an eyepiece heating strip wrapped around the reducer.
Gary
--------------------
Gary Honis
DSLR Modification Service
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Nils_Lars
Post Laureate
Reged: 01/04/08
Posts: 3443
Loc: Santa Cruz Mountains , CA
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Beutiful shot , looks like you have it all dialed in.
--------------------
Erik
Orion Atlas Self Hypertuned (EQMOD)
Orion ED 80
Williams Optics VII reducer
Celestron 8" SCT
Orion Starshoot Autoguider
PHD guide
Canon 400D Hap Griffin Mod w/Baader filter
Astronomik clip-in LP filter and 12nm Ha
Stilleto CVF and Bahtinov mask
Tamron 75-300mm&28-80mm lenses
NexImage webcam
http://www.flickr.com/photos/31986095@N05/
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walt r
Post Laureate
Reged: 02/13/07
Posts: 3463
Loc: Doylestown, PA
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Very nice image and great news on dialing in the system. The noise numbers are impressive.
--------------------
Walt
Obsession 18" f/4.45 #1370 AN/SC
MK67 Deluxe 6" f/12 Mak-Cass, Super Polaris GEM, JMI MicroMax DSC
DIY 60mm f/6 Achromat
Cookbook 245 CCD
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kingjamez
scholastic sledgehammer
Reged: 10/03/06
Posts: 991
Loc: Washington D.C.
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Gary, are you still on V3 of your cooler? It's getting you all the way down to 5 degrees? Those are some fantastic results!
-Jim
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C8 on Atlas with EQMOD
ETX125 UHTC
Celestron Onyx 80mm
Meade Walmart 60mm guide scope
Canon Xsi Modified w/IDAS LPR
Gen 3 NightVision Eyepiece
Aspiring Optician
Watch my Wiimote control Atlas:
http://www.youtube.com/watch?v=PnmkygmGNiM
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Hi Jim,
Yes, still using Version 3 of the cooler. I can't make it any smaller; it fits the camera like a glove. The reason it was keeping the camera at 5 degrees Fahrenheit last weekend was because the ambient temperature was in the 30's. I actually got less of a temperature drop than usual (up to a 44 degree drop) because I was using a heater to keep the front lens of the reducer free from fogging. So, there was more heat in the camera system for the cooler to dissipate. The heater strip is one I made for my binoviewer from nichrome wire and I'm sure it is putting out more heat than needed when being run flat out without a controller. I'll have to make one for the reducer or buy an eyepiece heater strip and use a controller.
Gary
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Gary Honis
DSLR Modification Service
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cvedeler
Carpal Tunnel
Reged: 12/20/05
Posts: 2163
Loc: Scottsdale, AZ
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Nice image Gary!
Do you find it worthwhile to cool the camera that much? I've been taking darks with my Canon 350 now that we are in a cold snap here in Phoenix (lows in the high 50's!) and find the camera MUCH MUCH more well behaved than when it is in the 90's and 100's where it is essentially useless. I'm so impressed with my darks at 60 degrees I wonder about the advantage of cooling the camera down to 5.
I would also be concerned about the health of the camera operating at those low temperatures. How about battery life or do you use an external power adapter?
--------------------
Chris Vedeler
Astro-Physics 160EDF
Astro-Physics 900GTO
Q453HR / QHY8 CCD camera
Canon 450XSi
----------------------------
www.aznightsky.com
Scottsdale, AZ
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Hi Chris,
Good points. Once the camera is below 50 degrees Fahrenheit I have found in general that noise is very low for moderate length exposures. Normally, at ambient temperatures near freezing I didn't think I would use the cooler; but I had it.....so I used it. Also, I just picked up an Ha filter and plan on taking exposures of 10 minutes or longer.
DSLR camera makers usually list an operating range beginning at 32 degrees F, but I have used my DSLRs during winter here in the Northeast many times to near 0 degrees F without problems. When handheld, you can swap the battery with a warm one from your pocket. At the scope I use the canon power supply for the 450D. Since the camera is in a sealed chamber, moisture is not a problem for the camera since it is in a dry environment and after the imaging session I keep the camera in the sealed container. I use desiccant and a desiccant indicator card that would change color if mositure is detected, but that hasn't happened so far.
Gary
--------------------
Gary Honis
DSLR Modification Service
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walt r
Post Laureate
Reged: 02/13/07
Posts: 3463
Loc: Doylestown, PA
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Even with winter temperatures there is the advantage of the "cooler" in that one can maintain the camera temperature at a set point. This helps ensure the Dark frames match the Flats and Lights for good correction. Makes processing easier and results in a better final image.
--------------------
Walt
Obsession 18" f/4.45 #1370 AN/SC
MK67 Deluxe 6" f/12 Mak-Cass, Super Polaris GEM, JMI MicroMax DSC
DIY 60mm f/6 Achromat
Cookbook 245 CCD
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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With cold winter temperatures having settled in here in the Northeast, the peltier DSLR cooler can take the 450D below 0 degrees Fahrenheit. Don't really need to go that low for noise reduction and I have some fear of operating the camera that cold for extended periods. So, I bought a variable power supply ($30) for controlling temperature of the cooler and posted some notes here:
http://www.ghonis2.ho8.com/rebelmod450d16g.html
Gary Honis
--------------------
Gary Honis
DSLR Modification Service
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cvedeler
Carpal Tunnel
Reged: 12/20/05
Posts: 2163
Loc: Scottsdale, AZ
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Very cool Gary! 
--------------------
Chris Vedeler
Astro-Physics 160EDF
Astro-Physics 900GTO
Q453HR / QHY8 CCD camera
Canon 450XSi
----------------------------
www.aznightsky.com
Scottsdale, AZ
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Gary Honis
Vendor-DSLR Mods
Reged: 12/15/04
Posts: 220
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Chris,
I was thinking maybe you wanted to try this power supply to see if you could get more cool out of your working DSLR cooler. The 15 volt setting is very tempting, but since you already burned up one peltier, I can understand the fear. 
Gary
--------------------
Gary Honis
DSLR Modification Service
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cvedeler
Carpal Tunnel
Reged: 12/20/05
Posts: 2163
Loc: Scottsdale, AZ
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Actually Gary I'm going to try a different approach entirely. I'm going to design the insulation around the box to allow me to place dry ice behind the copper box. I'm thinking that since I really don't need to cool the camera to -100F I will put a thin layer of insulation between the dry ice and the copper box to slow the cooling down. This will also prolong the life of the dry ice. According to my early web research I may be able to go 8 hours with a single 1" to 2" packing of dry ice. This will eliminate the need for an extra bulky battery in the field, as well as one less wire to the camera.
I'll run tests as to how much cooling I get with how much ice for how long to test the feasibility of the idea. It may be a pipe dream, but it won't cost much to test it out at this point.
My fears at this point are cooling the camera to much to fast and actually damaging it. I'll probably place a block of wood inside the box with my initial testing to see how well it performs with that before subjecting my camera to a test.
I'm thinking ahead to my 100F nights next summer. If I can design a system that can drop the camera temps to below 20 - 30F under those conditions I'll be quite happy. I don't think a standard peltier cooler is up to such a task.
--------------------
Chris Vedeler
Astro-Physics 160EDF
Astro-Physics 900GTO
Q453HR / QHY8 CCD camera
Canon 450XSi
----------------------------
www.aznightsky.com
Scottsdale, AZ
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cvedeler
Carpal Tunnel
Reged: 12/20/05
Posts: 2163
Loc: Scottsdale, AZ
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Here is some of my thinking regarding using dry ice.
It costs about $2 a pound so is quite cheap and is readily available.
A 1 inch by 6 inch by 4 inch area of dry ice (the area I'm planing on making behind the box) weighs 1.3lbs and contains 331 BTU of cold.
A 45 watt Peltier cooler is at best 10% efficient meaning it could generate only 15 BTU of cold per hour.
If the dry ice lasts 8 hours before it has sublimated that is 41 BTU per hour or almost 3x the cooling power of a 45 watt Peltier. Higher power Peltier's require a much more robust cooling system as I discovered with my 138 watt cooler making them impractical for this application.
Dry ice will probably weigh more than a Peltier and heat sink but it will not require any additional wiring to the box or a robust battery to run it all night.
Of course this is all theoretical at this point. I hope to modify my box in the next few days and run some tests with dry ice to see how feasible this idea is in real life.
--------------------
Chris Vedeler
Astro-Physics 160EDF
Astro-Physics 900GTO
Q453HR / QHY8 CCD camera
Canon 450XSi
----------------------------
www.aznightsky.com
Scottsdale, AZ
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cvedeler
Carpal Tunnel
Reged: 12/20/05
Posts: 2163
Loc: Scottsdale, AZ
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Dry ice is some powerful stuff! I haven't modified my box yet but decided to just put a 2" x 3" chunk of it in the box and put my thermometer probe hanging in the air. It went from 73F to -34F in less than 8 minutes! My box was crackly and popping along the way.
So we know it is cold, but can it last? I hope to modify my box for a real test tonight.
--------------------
Chris Vedeler
Astro-Physics 160EDF
Astro-Physics 900GTO
Q453HR / QHY8 CCD camera
Canon 450XSi
----------------------------
www.aznightsky.com
Scottsdale, AZ
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Kentari
scholastic sledgehammer
Reged: 11/19/06
Posts: 794
Loc: Belgium
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Make sure not to make it airtight or that box is going to pop real hard!
Cool experiment though... I look forward to the result.
I'm pondering the purchase of a second 40D to mod and freeze ... The are becoming interesting on the used market.
Koen
--------------------
Darkstar 355 f/5 Dobsonian
Orion UK 8" f/4.5 Newtonian and WO ZS 80 FD on Losmandy GM8
Canon 20D DIY mod with Baader filter
A bunch of lenses: 10-22mm f/3.5-4.5, 17-40mm f/4, 50mm f/1.4, 70-200mm f/2.8, 300mm f/2.8
www.koenvangorp.be
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cvedeler
Carpal Tunnel
Reged: 12/20/05
Posts: 2163
Loc: Scottsdale, AZ
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Yea Koen I've watched those Youtube videos where kids explode pop bottles using dry ice and water. Air tight = bad. However I need to keep it sort of tight so it will cool the camera slowly and evenly and stay as cold as possible as long as possible. I figure with my engineering aptitude, if I try and make it air tight it will be just leaky enough...  
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Chris Vedeler
Astro-Physics 160EDF
Astro-Physics 900GTO
Q453HR / QHY8 CCD camera
Canon 450XSi
----------------------------
www.aznightsky.com
Scottsdale, AZ
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Strgazr27
Vendor - Deep Space Mods and Composites
Reged: 10/04/04
Posts: 6984
Loc: StonyHill Observatory
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Chris,
Although that is some wicked cooling your treading on "Dry Ice" so to speak. There is no regulation, no safety net and man have you ever grabbed a pice of dry ice without gloves on Lol. My biggest fear is cooling the components way faster than they can handle.
Good luck with your tests....I see a QHY8 in your future Lol.
--------------------
Bobby
StonyHill Observatory
Skywatcher EQ6 Pro (On it's way)
AT 130 F/6 Prototype
Royce 10" f/4 Astrograph (Under Construction)
Self Modded 40D
70-200 F2.8 L IS
SSAG
YAHOO TMB 130SS Group
Astronomy Technologies Yahoo Group
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walt r
Post Laureate
Reged: 02/13/07
Posts: 3463
Loc: Doylestown, PA
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Interesting idea. As posted above I too would be concerned about cooling too low and too fast. Maybe have the dry ice in contact with the back (component) side of a heat sink with the fins in the camera compartment. A fan on the fins could circulate the camera compartment air to cool the camera. Like the TE cooling except with the dry ice on the cold side.
Any thoughts anyone?
--------------------
Walt
Obsession 18" f/4.45 #1370 AN/SC
MK67 Deluxe 6" f/12 Mak-Cass, Super Polaris GEM, JMI MicroMax DSC
DIY 60mm f/6 Achromat
Cookbook 245 CCD
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cvedeler
Carpal Tunnel
Reged: 12/20/05
Posts: 2163
Loc: Scottsdale, AZ
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Thanks Bobby. I had no intention of putting dry ice in the camera compartment because I think you are right that it would be too much cold too fast for the camera to handle. Plastic would likely crack and the camera could very easily be damaged. The dry ice would also disappear far to fast to be useful for several hours of astrophotography per target. My plan is to have a separate insulated compartment behind the copper box to slowly leak the cold to the camera. I will try different amounts of insulation (something between paper to 5mm of foam) between the copper box and the dry ice until I can maintain perhaps a 50F difference between ambient for as long as possible. This will also prolong the life of the dry ice making it more feasible in that regard too. I also plan on using an internal fan just like Gary's to help circulate the cold within the box just like you suggested Walt. In practice I'm just modifying the source of cold and not the application that Gary has proven with his great project.
My test this afternoon was just to see for myself what kind of cold power I was dealing with. Now I have to figure out a way to tame it.
I'll hopefully get it all put together in the next day or so (perhaps tonight) and post pictures and results here.
--------------------
Chris Vedeler
Astro-Physics 160EDF
Astro-Physics 900GTO
Q453HR / QHY8 CCD camera
Canon 450XSi
----------------------------
www.aznightsky.com
Scottsdale, AZ
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Freddy WILLEMS
Carpal Tunnel
Reged: 11/13/05
Posts: 2557
Loc: Hawaii, Honolulu
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I'm working on one to, will post images soon.
Freddy
--------------------
Freddy
Meade 14" LX200 GPS UHTC GPS on permanent pier
Celestron C 14" Peltier cooled for planetary imaging.
Meade 10" LX200 & TITAN 50:1 mount Gemini 'go to'
Meade 127 mm f/9 APO & TITAN 50:1 mount Gemini 'go to'
W/O 102 mm f/7 APO doublet
Orion 80 mm f/7 ED
DFK 21AU04.AS
ToUcam 840 II pro
Canon 10D Unmoddified
Canon 40D Hutech moddified
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