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Patrick,

Three leveling screws would be easier to operate.  In fact, one often
only needs to operate two of the three to level a device.  Of course
a bubble level is easier to use than a uni-directional level.
Perhaps course level with a bubble level and then fine with the
machinist's.

Fred Hebard
at the other end of your state, about the same latitude.


On Mar 23, 2011, at 4:16 PM, Patrick Goold wrote:

> I have finally put together an artificial horizon using a front-
> surface mirror.  My hope is to be able to do star and planets
> sights with it, which I cannot do with my Davis artificial
> horizon.  I found an inexpensive optical quality mirror on-line.  I
> drilled and tapped four holes in a cheap polypro cutting board for
> inch-and-a-quarter-long 3/8th-inch machine-thread bolts to serve as
> levelers and then attached the mirror using standard bathroom
> mirror brackets.  The trick will be getting the thing adequately
> level.   William Morris kindly supplied me with a very sensitive
> level vial.  It is not mounted to the device.  I set it diagonally
> across the mirror and level it, move it to the other diagonal and
> repeat, switch it end to end and repeat both those steps and then
> repeat as necessary.   A picture of this simple apparatus is
> attached.  Any suggestions about how to improve it (without vastly
> increasing its cost) would be welcome.
>
> I haven't yet taken any sights using it.  It takes twenty minutes
> to level the thing, sitting at my dining room table.  That is,
> provided no one is moving about on the ground floor of my house
> while I am doing it.   The level is very sensitive.  It will not be
> easy getting it set up outside.
>
>
>
> --
> Dr. Patrick Goold
> Department of Philosophy
> Virginia Wesleyan College
> Norfolk, VA 23502
> 757 455 3357
>
> Charles Olson: "Love the World -- and stay inside it."
>
> 

   

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