Hi, i´d like to share my experience. i did many tests with different canon dslr sensors and it seems that every sensor is a little different with scratching. i didn´t get a real good result. either the sensor was death or had sratches, but no one was useful. so i start to give the polish method a try. What can i say? every sensor i debayered was a fully success. so here is my howto list: - remove the sensor and the top glass (heat helps a lot to do this) - use "uhu endfest 300" for the bonding wires to protect - use some leather rods, meguiars plastx and ethanol (to thin down the plastix) to remove the microlenses and the cfa (takes 30 minutes for rough pollish) - q-tip, plastx and ethanol for fine polish the hole sensor - ar-coated glass from edmund for top cover - ar coated glass with heating wire instead of the shutter cleaning piezo and low pass filter Here some pictures (sorry for the bad "screenshots"): Picture of a streched flat before i fine polish the sensor extensively: Here after 10 minutes fine polish, both picture are streched to max in fitswork: Heres the first test, 5 x 600 seconds with 12nm h-alpha filter (without cooling): So after this successfull test i start to build the active cooling with a high quality 2 stage peltier from quick-cool. these peltiers are much more efficient than the cheaper chinese ones. many parts are made out of carbon fiber. there is also an arduino controller for the little display i added inside the flash-head. here´s a picture of the nearly finished camera: and here the display in detail, it shows the sensor temperature, the surrounding temperature, air pressure and the current through the peltier. i get a delta of nearly 30°celsius: D=Digital a= astronomy c= cooled m= mono-debayered: markus