"Joseph Gwinn" wrote in message
...
In article ,
Wes wrote:

Joseph Gwinn wrote:

As for manufacture by a HSM, either approach is practical, but the Wyler
approach is far simpler mechanically. In either case, the electronics
part is dead simple by present-day standards, but was a big deal back in
the 1960s and 1970s.


Are you planning to try it? Btw, thanks for the list of patents.

I am thinking about making a level. Don't know if I'll really do it.
Probably depends on how practical an approach I can dream up.

snip

If I wanted to make a precision level today - more precise than a
starett/vis master level, then I think I'd do the following

1.erect a perpendicular over the base material - one might use a surface
plate or other optically flat material for the base.

2. drop a penduluum from the perpendicular - longer is better so long as the
perpendicular in fact remains perpendicular

3. place a mirror at the end of the penduluum, and arrange mirrors along the
base to direct beams from a low powered laser. Mirror at base shoudl have
an angled and a straight part

4. use an interferrometer to measure the final centering of the penduluum -
first, just use the laser to roughly center by using the angled mirror to
form an optical amplifier and use a wall, maybe 20 feet away to get the
thing aproximately centered (this should get you to a micro inch or so).
After that, use interferrometry, this will get you to 1/2 wavelenght - so
depending on your choice of emitter, somewhere in the 200 to 500 angstrom
range. With a 1 meter perpendicular, that should give you what .... inverse
sine of 1E-8=?? - well, using small angle aproximation, 1e-8 radians

Is that good enough?