CCD noise refers to unwanted signals created in CCD images. CCD cameras image celestial objects by using millions of light sensitive pixels to collect incoming light. When light strikes a pixel a small electrical current is recorded. However, heat generated within the device also produces electrical currents and this is referred to as thermal noise. The noise can be reduced by cooling the device using fans or Peltier cooling systems. A different type of noise is intrinsic noise, which is contained in the image itself.