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The artificial star is a great help and the ease is a stable light source with no atmospherics to worry about but the true test comes when pointing at the sky. Picking a star near the zenith and seeing the performace with full weight on the mirror shows up any problem. Also I won't tell you how to suck eggs but the sequence of adjust secondary, adjust primary then adjust secondary again is vital. Once you have finished this process you must take a picture with your defocused star in the middle and each of the four corners of your field this will reveal any distortions that remain. If you find (as I did ) that you have one corner that is 'out'. you then adjust the primary into the direction of the error. This rapidly overcomes most of the collimation error but be careful it gets down to a ridiculously fine amount of adjustment. mine is now close but I probably have about a 1/16 of a turn left to get it right!!
good luck
Paul
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