NavList:

Richard suggested:

>> Now if there were only some easy way you could keep the position
>> of the sextant the same, and tip your head from upright to
>> horizontal, then you would be testing only the astigmatism of the
>> one eye.  A clamp and sturdy tripod, perhaps?>

Bill replied:

> I can do that with relative
> ease, with the minor exception of keeping tangency in the middle of the
> scope over any prolonged period of time.

Red suggested

> What about using a pinhole lens to accomplish this? A piece of black cardboard
> the size of a quarter (whatever fits securely in the lens, immediately in
> front
> of your eye) with a largish pinhole in the middle of it. That will pretty much
> restrict your eye to the same location, pretty much centered in the lens.


Now we are cooking, figuratively and literally. 87F, 64% humidity, heat
index in the shade 100F, 110-115 in the sun.  That will steam the wrinkles
out of your shorts.

Set up approx. 15:05 EDT, and got a short break in the clod cover about
16:00. I was able to get off 10 observations on the arc before the hole
closed.

Vertical sextant, all measurements on the arc.

      Head upright  Head horizontal, left ear up
      32.0          32.6
      32.1          32.4
      32.0          32.2
      32.2          32.5
      32.0          32.6

Mean  32.06         32.42
sigma   .09          .17

Difference  |0.36'|

I will need to do more tests, on and off the arc, but preliminary results
support other test results and the trend does look like the old Mach 1
eyeball is out of shape.

Thanks

Bill


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