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Alex,
I stand corrected on my comments reguarding perp check procedures as stated
in the Tamaya owner's manual that I wrote of yesterday.
As for stating not moving one's head during the check/adjustment it appears
that is one of my procedures.It is NOT stated in the manual.
The following is taken directly from the Tamaya manual in reguards to front
silvered index mirrors.

"FRONT SURFACE MIRRORS
If you need to replace your Index mirror with a mirror that is silvered on
the front surface,the silvering will be located forward of the axis of
rotation of the sextant arm.With this configuration,the normal method of
useing the reflected arc will not be adequate.You will notice that as the
eye is moved above the sextant,the appearance of the reflected arc
changes.The only correct observation point is with the eyes on a level with
the sextant frame itself.however,in this position,nothing of the reflected
arc can be observed.Thus,the use of calibrating cylinders placed on the
sextant arc is required.the eyes can then be positioned level with the top
of the calibration cylinders.

METHOD OF USE
Lay the sextant on its side with the arc scale facing up upon a flat
plane.Place the 1st cylinder upright covering the 0* mark on the sextant
arc.Place the 2nd cylinder upright on the 110* mark of the sextant
arc.Course adjust the index arm to 35* on the sextant scale.With your eye
about 1 ft from the sextant,and looking between the horizon and index
mirrors,observe the 1st cylinder.Now slowly  move your head to the left
untill the index mirror starts to obscure the left side of the 1st
cylinder.At the same time you will notice the reflected image of the 2nd
cylinder begin to appear where the 1st cylinder was.The result is what
appears to be an image of 1 cylinder,but is actually a composite of both.
To make adjustments for perpendicularity,move your line of sight to be level
with the tops of the cylinders.Turn the adjusting screw on the index mirror
frame untill the heights of the 2 cylinder images appear equal.You have now
removed the error of non-perendicularity between the index mirror and
sextant frame"

So,I was incorrect in that there is a specified spot to place one's eyes as
stated in the manual while doing this procedure.

   

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