Dumb Collimation Question

I have probably a dumb collimation question…

I have noticed that a star in the center of my view in the eyepiece does not necessarily end up in the center of my chip when I put my webcam in. If the difference is enough, a star that looked collimated on axis in the eyepiece, may look out of collimation when centered on the screen of the webcam image. If there is an offset, should I collimate against the screen view or the eyepiece?

Am I making any sense? :S

Thanks in Advance,
Jason Irby

The offset will probably have no effect. Webcam chips are
pretty small. What looks like a large offset on
the screen is probably less than a millimeter at the focal
plane.