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    Re: Adjusting perpedicularity of the Index Mirror
    From: Alexandre Eremenko
    Date: 2004 Oct 11, 18:13 -0500

    Dear Doug,
    Whether you use dominoes or Celestaire cylinders,
    or special visors (supplied by the manufacturers of
    SNO-T), or just the plane old test ("looking at the frame")
    my question remains the same:
    Where should your eye be with respect to the sextant frame
    dusing the test? This evidently DOES matter!
    By moving your eye up and down a little
    (perpendicular to the sextant
    frame) you can see your dominoes edges near the upper part
    or medium part or lover part of the right edge of the index mirror
    (I assume the sextant frame is in horizontal position).
    If you do this, you notice that the alignment of the dominoe edges
    cannot be reached at every point of the right edge of the index
    mirror, but only at ONE point of this edge. WHICH point should
    this be? The middle? Or the lower (closest to the frame) point?
    On Mon, 11 Oct 2004, Royer, Doug wrote:
    > Bruce,
    > It is stated that all front coated index mirrors can not be checked for
    > perpendicularity in the old way of useing the arc's relected image.You will
    > not get the mirror perp useing that old method.I've used dice before and
    > have since found useing dominoes to work even better.Same procedure as you
    > stated in your post on this matter.
    > My MS-733 has the cal cylinders and I've used them in the past.I really
    > prefer useing the dominoes though.They are square.They sit on more arc area
    > than do the cylinders or vanes.And they only cost around $5.00 for a
    > lifetime supply.Plus you can play dominoes with them if you get bored.

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