ATM sub-arcsec micrometer precision

[Dominic-Luc Webb molmed <Dominic.Luc-Webb@molmed.ki.se>]

I finally got to borrow the Ingalls Amateur 
Telescope Making, Advanced edition. There is 
a chapter about micrometers (partly why I 
wanted this book). I'm not sure how much has 
changed since 1940's. I am hoping someone has 
some suggestions to following because it 
seemed like such a nifty gadget:

1) Has anyone here ever built a micrometer?

2) Is it possible to accurately split and 
measure angular distances between binaries that 
are less than 2" apart, as Ingalls did, assuming 
the rest of the optical system can resolve it 
(i.e., I refer to amateurs)?

3) I suspect (2) above is true, so, is such a 
micrometer something I can build with a 
couple of biconvex lens halves and a fine threaded 
screw or is this is necessarily a precision 
machined commercial item?


Cheers,



Dominic

North 59 37' 30"
East  17 48' 10"