Extremely cool! (pun intended) -- Joe --- On Mon, 11/16/09, David Rankin <David@rankinstudio.com> wrote: From: David Rankin <David@rankinstudio.com> Subject: [Utah-astronomy] Cooling Modification for Canon Rebel To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Monday, November 16, 2009, 9:16 PM Here is a project I've been working on based of another modification done by a member on cloudy nights for anyone who is interested. The idea for those not acquainted with this, is to cool the sensor of the camera down as much as possible. This reduces your background noise and makes your frames retain much more of the original light signal coming off the object your shooting. It helps create a much better signal to noise ratio, which makes for higher quality stacks of images with less light frames. I based my "cold finger" design off of the one by Anat here http://thaiastro.nectec.or.th/hypermod/ My goal was to preserve the functionality of the camera after the modification for daytime use as well, unlike what Anat and others have done, which is to totally convert the DSLR into an astro-only camera. The cold finger is the aluminum slid under the circuit board for the cmos, and above the actual cmos itself. This is then all sealed up with hot glue to prevent moisture buildup when cooling. Images from my version of the hyper mod. http://www.rankinstudio.com/dnloads/mod1.JPG http://www.rankinstudio.com/dnloads/mod2.JPG http://www.rankinstudio.com/dnloads/mod3.JPG http://www.rankinstudio.com/dnloads/mod4.JPG http://www.rankinstudio.com/dnloads/testrun.jpg Below are crops from the center of the sensor uncooled, and cooled. Can see a significant noise drop. I am not sure what the exact temperature of the sensor is as I didn't have a temperature gauge to install there, but the measurement where the cold finger entered the camera was around 45 deg F after only 4 or 5 minutes of cooling. These are dark frames (taken with the lens covered to show the noise signal) 4 minutes long at very high sensitivity/gain ISO 1600. http://www.rankinstudio.com/temptest <http://rankinstudio.com/temptest> Ill update when it is finished. Cheers, David Rankin _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com