A laser is not effective for collimating a SCT. Centering the spot, as would be done for a Newtonian, is likely to give very poor results.
A reliable method is given in here:
http://skywatch.brainiac.com/collimation.pdf
During the day I don't bother with a bought artificial star, but just observe a small white paint spot on the chimney of a house down the street. Any small, sufficiently bright and distant object will work.