collimation

I recently moved my scope off the pier to take to a star party for the community to learn about astronomy. When I put it back on the pier it is out of collimation and I can't seem to get it back. The problem is no matter what screw I turn, I can't get the ring centred.
I have a 8" SCT LX90 w/bob's knobs. but my arms are not long enough to look into the eyepiece and turn the knobs at the same time.
I would sure appreciate any suggestions, thanks guys, bob

robert black said:

I recently moved my scope off the pier to take to a star party for the community to learn about astronomy. When I put it back on the pier it is out of collimation and I can't seem to get it back. The problem is no matter what screw I turn, I can't get the ring centred.
I have a 8" SCT LX90 w/bob's knobs. but my arms are not long enough to look into the eyepiece and turn the knobs at the same time.
I would sure appreciate any suggestions, thanks guys, bob

Not sure what you mean by "ring." Put Polaris in the field, and defocus slightly until you see a series of rings. Not so much that it looks like a great big donut. Adjust screws by small amounts, by tightening them, until the rings are concentric. One trick is to put the side of the star that is "squished" against the edge of the field and adjust the screw/screws that move it back to the center. Only adjust by tightening. Only when a screw is snug and you need to continue in the same direction should you loosen its opposite number(s). Do that and your scope will maintain collimation even after a road trip.