On 14/04/2021 09:58, Clive Arthur wrote:
On 13/04/2021 22:01, Theo wrote:
Fredxx wrote:
Just keep an eye out for any changes.

There might be something you can do in terms of fixing some cheap laser
pointers (firmly) to the structure, and marking out where the beams land.
Then go at different times of day and see if there's any difference.
(turning them off when not in use, obviously!)

(I'm not sure laser pointers are collimated enough, but worth a try
before
going for anything fancier)

Theo


If you have any small cracks, glueing microscope slides across them is a
good way to check for movement.Â* You can pick up a pack of these on eBay
for notalot.


With something so important I'd prefer a measure which avoids the false
alarm of a glass slide broken without developing movement - eg

https://www.sccssurvey.co.uk/crack-m...k-monitor.html



--
Robin
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