Peltier Cooling of Modified Canon Digital Rebel XSi (450D)

Version III

by Gary Honis

UPDATE : I can provide a low cost modification service to convert your Canon DSLR camera for astro or infrared imaging. CLICK HERE for details.

The first version of the cooling system I made for the Canon modified 450D did not cool the camera as well as I liked. It used a coffee canister as the cooling chamber and its metal was not a good conductor. The second version of the cooling system used part of the original cooler for the cooling chamber, instead of the coffee canister. It cooled the camera very well, dropping its temperature 38 degrees Fahrenheit. The third version of the cooling system is discussed here. It is smaller and lighter than the previous versions and cools even better than the second version providing an even greater temperature drop of 43.7 degrees Fahrenheit.

The original Cooler is branded "RubberMaid", but the cooler is made by Vector, Inc. and branded under other names as well. It operates on 12 volts DC and Vector also makes a 6-Amp AC/DC converter to operate the cooler using 120 volts AC.

Below are some quick images of how I used a peltier device from the 9 can beverage cooler ($25), a sheet of aluminum ($10), and a styrofoam cooler ($3) to build a peltier cooling system for my modified Canon XSi (450D).

Detailed assembly instructions for anyone wanting to build a similar cooler can be seen HERE.

Since the 450D (XSi) and the 1000D (XS) have the same height and depth, this cooler fits the 1000D (XS) as well.

In the image below the peltier cooled Canon XSi (on right) is in the focuser of an Astro-Tech 127mm triplet refractor. In the background is a Meade DSI Pro imager in the focuser of an Orion ED80 used for autoguiding:

The following photos were taken during the assembly process:

Peltier, fan and switch parts removed from the cooler:

Fan remounted to heat sink:

The cooler's on/off and cold/warm switch with LED lights was taken off cooler and mounted in a project box. Switch was not mounted on cooler but instead placed on cables four feet from cooler to help keep the cooler weight low.

A very thin .025 sheet of aluminum (1/40 inch) is formed into a rectangular shape just large enough to fit the Canon 450D body:

Holes are made for the 2" Barrel to focuser and for the camera's flash nosepiece and the peltier/fan assembly is attached:

Placed a small 12 volt heatsink/fan inside to circulate cold air:

Aluminum cooling chamber is covered with light pieces of styrofoam for insulation:

Images of cooler on scope:

Version III - Dark Frame and Cooling Tests:

I used two temperature probes to test the cooling effect while taking dark frame images. One probe was placed on the aluminum chamber wall and the other on the camera body. I took dark frames every five minutes at ISO 1600 and measured the air temperature inside the cooler at the two probe positions. The ambient temperature during testing was 77.4 degrees. A plot of the 43.7 degree Fahrenheit temperature drop of the cooler over time is shown in the graph below:

I was very pleased with the above temperature drop over time as measured by the two probes. It was an improvement in both the rate of temperature drop and maximum temperature drop achieved over Version II of the cooler, probably because of the smaller size of the cooling chamber of Version III.

Version III - Dark Frame Results:

For the graph below, I converted the ISO 1600 Canon five-minute dark frame raws to TIFs using Canon's Digital Photo Professional and then recorded the standard deviation of the whole color image (4272 X 2848 pixels) for each dark frame. Note the comparison to the dark frames of the Version II cooler. It shows that the smaller size of the Version III cooler and one internal fan as opposed to two internal fans, provides the same reduction in dark frame noise.

Notice in the above graph that noise increases over the first ten minutes (the first two 5-minute exposures). It shows the delay in cooling of the camera's imaging chip and electronics. I'll have to do a test with no cooling (camera outside of the cooler) and add the results to the above graph to see how much of a benefit the cooler provides over non-cooling.

Version III - Dark Frames:

Below is a comparison of the 342 X 342 pixel center crops of the five-minute dark frames at ISO 1600 taken at ambient temperature (77.4 degrees Fahrenheit) and after one hour of cooling ( 37.6 degrees) and two hours of cooling ( 34.0 degrees) cooler temperature:

Detailed assembly instructions for anyone wanting to build a similar cooler can be seen HERE.

First Light image of the Veil Nebula with the pelteir cooled Canon 450D can be seen HERE.

UPDATE: 08/30/08

M31 Andromeda Galaxy with pelteir cooled Canon 450D can be seen HERE.

UPDATE: 9/4-7/08

M33 - Pinwheel Galaxy and NGC 7635 Bubble Nebula with M52 Open Cluster with pelteir cooled Canon 450D from Cherry Springs Dark Sky Park can be seen HERE.

UPDATE: Cherry Springs Dark Sky Park - 10/3-4, 2008:

IC434 & Barnard 33 - Horsehead Nebula, IC 1805 - Heart Nebula, NGC 253 - Sculptor Galaxy, NGC 7331 Galaxy & Stephan's Quintet, NGC 884 &NGC 869 - Perseus Double Cluster with peltier cooled Canon 450D from Cherry Springs Dark Sky Park can be seen HERE.

UPDATE: Cherry Springs Dark Sky Park - 10/30-11/1, 2008:

M42 Orion Nebula and NGC 1977 Running Man Nebula, NGC 1499 California Nebula, NGC 281 Pacman Nebula and IC 1848 Soul Nebula with peltier cooled Canon 450D from Cherry Springs Dark Sky Park can be seen HERE.

More recent images taken with the peltier cooled Canon 450D can be found HERE.


Removal of Canon XSi (450D) IR Cut Filter for Astrophotography:




Canon Digital Rebel - Canon Digital DSLR - Digital Camera - Canon 450D - Canon Xsi - Canon 1000D - Canon XS - Canon Digital Rebel XT - Canon Digital Rebel 350 - Canon Digital Rebel 350XT

Astro Imaging with Canon Digital Rebel XT Camera