The transfer rate of a WebCam requires a lossy compression to achieve the specified 30fps frame rate at full resolution. These losses will degrade the image quality for astro imaging and must be minimized therefore.

As the CCD has true 640x480 photosites but covered by a bayer filter one does disable the degrading interpolation used for color CCD chips to let pass the raw image to the computer. Taking only the Y plane (luminance channel) one has the least compression applied - rebuilding the color image on the receiving computer will usually lead to a better final image.

Using again a clever program ;-) one can disable the cameras de-bayer algorithm and reduce the compression as best as possible the which leaves all pixels un-interpolated pass through up to the receiving end.