NavList:

Here are my thoughts of how to create a new AH.

1) It should be a front surface mirror, with an accuracy of roughly lamda/4.  This will provide the requisite thickness to preclude the mirror from deformation when supported.

2) the support should be a kinematic mount.  This is typically a three point  adjustable mount, so as to be able to "dial in" horizontal.  The supports would be 120° apart.

3) the MEMS devices described elsewhere in this thread should be directly affixed to the front surface of the front surface mirror.

4) My preference would be three such MEMS devices, 120° apart, and 60° out of phase relative to the kinematic support.  Each essentially will measure horizontal, directly betwixt each support.

5) a digital readout of each MEMS, with an ability to set an index error of each, as we may have glued the device down not parallel to the mirror face.

In combination, this will permit us to set up the AH, quickly, and to far greater precision than would be had with most others devices proposed thus far.

In practice, we could simply adjust the kinematic by selecting one leg as the fixed member.  Adjust leg number 2, until the MEMS between 1 & 2 reads horizontal.  Adjust leg number 3 until the other two MEMS read horizontal (rotating around the horizontal line formed by legs 1&2).  This may require 2, or at most 3 rounds, depending upon the smoothness of the kinematic contact points.

Brad