Image stacking is a procedure that astrophotographers perform in order to extract a low-noise image from a sequence of photos of a certain sky object. Some preliminary operations are performed on images in order to compensate for image artifacts generated by the atmosphere (e.g. blur, distortion, etc...); when all the images are perfectly aligned and sized the final image is computed by averaging. There is a number of existing applications for this procedure, but as far as we know none is written in Java� and open source. pleiades will try to demonstrate that Java� can be a profitable programming language for the amateur astrophotographer community too, also because it opens the door to easier distributed computing.