[rrussell1962]

Alex, I have a Nexstar 8SE. The three star alignment is used only in the alignment option where you select three bright stars (I think it also works with other objects) without needing to know what they are. The only function of the third object selected is as an internal check that the program has correctly "guessed" what the other two are by checking for three bright objects whose angular separations match where the mount has slewed. I am pretty sure there is no mount modelling involved. I do find though that realigning can improve the alignment accuracy. I don't know why though! My Vixen Skysensor picks the best three alignment points when subsequent alignment points are added. I have no idea if the Nexstar or CPC does the same when alignment points are replaced.