[ATM] Question on my lap for 8" F6

[bobmay at nethere.com (Bob May)]

A little hint.
I set the scale that most dial indicators allow to be moved to 0 the pointer
at the center zone.  This allows easier entry of numbers to the various
reduction programs.  As the zones are measured, the dial indicator will
indicate larger numbers with the length of the path from the tester to the
mirror increasing as you go out towards the edge of the mirror zones.
You sort of indicate that this is happening with the motion of the screw but
since you haven't indicated a lot of the other variables in the tester like
which end the screw is on (front or back) as the back end away from the
mirror is where most of us put the movement screw.  The dial indicator is
also a variable as one way it measures higher while the other way it
measures lower and that is depending upon which direction the table moves
relative to the indicator.  You should always assume higher numbers when the
table is moving away from the mirror and lower numbers when the table is
moving towards the mirror as you are basically measuring the ROC of the
mirror with a big number subtracted from the length to make the job of
copying the numbers easier for you.
I hope that this helps.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net