[Andrew C]

Thanks folks for all the ideas - your detailed reply especially Rob, because mine is the six screw type you described, and being able to remove just the laser and not the whole assembly with attendant risk of disturbing the alignment screws is just what I want.

Our days (in Alice Springs) are very pleasant at this time of year, but the nights are clear and cold, mostly down around 0-3 degrees min, so the old laser will be much happier if it spends a bit of time warming up between sightings.

Cheers,

Andrew