[Sharnbrook (Mike)]

I have only ever attended one commercial observatory, and that was at the Cosmos Centre in Charleville a few months ago. I was somewhat surprised that we were not allowed to adjust the focus when we were observing, and I wonder whether this is standard procedure? Whenever I take my scope to Public Sky nights, it never bothers me if people (adults anyway) adjust focus on my C 9.25, even if they end up getting it way out of focus. I really can't see the point of having a "fixed focus for all", but maybe someone can enlighten me on what happens at other observatories.