I was intrigued by this interesting design:
https://www.huberlab.org/resources/opti ... nt-device/
It works on the same basic principle as an Engineer’s tool devised by the great Dan Gelbart
and featured a couple of minutes into this video:
https://youtu.be/otSjut1iGGk?feature=shared
MichaelG.
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Edit: __ More information here:
https://opg.optica.org/boe/fulltext.cfm ... &id=395204
Optical Alignment Device
Optical Alignment Device
Too many 'projects'