What are some uses for L-Bar prism's?

L-Bar Monitoring Prism | Sales, Rentals & Support | Specto Technology

See the video. The last prism that's discussed has a rain and solar hood. Pretty inventive!

Also, from https://www.berntsen.com/Surveying/Survey-Prisms/L-Bar-Mini-Prisms#:~:text=L-Bar%20Mini%20Prisms,-The%20SECO%206600&text=These%20prisms%20are%20perfect%20for,resistance%20against%20moisture%20and%20dust

These prisms are perfect for deformation or mining surveys, land surveys, mining, tunneling, rail, monitoring, and other places where a permanent mounting is needed. Anodized aluminum construction offers durability along with resistance against moisture and dust.

I still have 2 in use???

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We use similar ones for long term monitoring, where you can get in to make the original mounting, but then can't easily get back for long term maintenance. Because monitoring (should) always involve taking the same shots from the same position - it's the change that is important - then prism constants, etc. don't come into it. Durability is all. If/when the monitoring finishes we would recover prism if suitable access became available.

Considered expendable items on any long-term monitoring project, I buy them by the case.?ÿ They are permanently affixed to the structure/face being monitored via anchor bolts.?ÿ Setting them is usually real fun and involves some kind of lift or rope work.?ÿ For points that may be susceptible to vandalism and/or have easy access, I use an inset plug (similar to the Bernsten monuments) with an 8 mm female thread that will except a special prism mount that can be easily removed.?ÿ Like Chris points out, since you are for change.?ÿ In fact, for long term real-time monitoring, the instrument can shot through single pane glass without issue.?ÿ?ÿ

@john-putnam?ÿ

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Posted by: @john-putnam

In fact, for long term real-time monitoring, the instrument can shot through single pane glass without issue.?ÿ?ÿ

Yes, but only as long as the window frame doesn't warp and change the angle of incidence - don't ask how I know!

@chris-mills?ÿ

Wow!