In my experience I have found lasers worse than useless for collimating Newtonians. See the June 2002 issue of Sky and Telescope for an explanation of the problems. As a test I set up a Newtonian telescope with the diagonal offset almost an inch in the wrong direction and by tilting the diagonal and adjusting the main mirror the laser converged as it is supposed to do; but the star images were terrible. A sight tube, Chesire and autocollimator are far superior for collimation. Several times I have seen laser collimated telescopes that were dramatically out of collimation with shadow of the secondary far off to one side. I have not tried the new holographic lasers that project a pattern so I can't comment on them. Clear Skies Don Colton