NavList:

1,2) With an a.h., the vertical is automatic; there's no "swinging" to get the right angle as there is with a sea horizon. Lining up the two images is all you need to do.

BTW, that "article suggesting a tilt of a couple of degrees could introduce 7 miles of error" is an exaggeration. But it depends on the details.

3) No. Use whatever eye makes you more comfortable. Don't forget that you can change the focus of the telescope, even on a plastic Davis sextant. You may want to experiment with that with both eyes.

4) Yes, stars can be easier to see when you move them to one side or the other of the field of view since you're reflecting from different part of the horizon mirror. If you're too far to one side or the other, this introduces a small collimation error. This is certainly insignificant for angles below 60 degrees given the level of accuracy of a Davis sextant, but since you're using an a.h., you may want to take care to make the final adjustment near the center of the field of view when the angle measured (double the altitude) is greater than 60.

-FER

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