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    Re: Making an artificial horizon
    From: Gary LaPook
    Date: 2011 Jan 21, 01:13 -0800
    I have no problem shooting Polaris which is only second magnitude.

    gl

    --- On Thu, 1/20/11, Patrick Goold <goold{at}vwc.edu> wrote:

    From: Patrick Goold <goold{at}vwc.edu>
    Subject: [NavList] Re: Making an artificial horizon
    To: NavList@fer3.com
    Date: Thursday, January 20, 2011, 6:01 AM

    Gary,
    Nice!  Is it reflective enough to get star sights or even just Jupiter?  How much Hg would it take to work a Davis AH?  United Nuclear asks $45/ounce.   Do you have a cheaper source?

    Patrick

    On Wed, Jan 19, 2011 at 9:15 PM, Gary LaPook <glapook---.net> wrote:

    I think we have all had the experience, when using an artificial horizon, that just as you are ready to
    take the reading a puff of wind ripples the surface. I finally got around to making an enclosure to
    prevent this. I purchased two 5 by 7 inch pieces of glass, sold to replace broken glass in picture
    frames at a craft shop, four dollars each. (The also come in larger sizes.) I taped one edge of the
    glass together with clear packing tape. I used a piece of the cardboard packaging to make a base by
    using blue masking tape to tape the bases of the glass to this cardboard, creating an equilateral
    triangle. I then used other pieces of the packaging, cut into triangles, to make the sides, one attached
    all around with tape and the other attached only to the base piece so that it can be opened to insert
    the small bowl of liquid, I use mercury. This side is held closed with a small piece of tape. I cut a
    circular opening in a piece of cardboard to place over the bowl of mercury to act as a stop to prevent
    seeing the edges of the liquid where the horizontal surface is distorted by a meniscus. I have
    attached several photos of this, one showing the moon’s reflection peeking around my chimney.

    gl
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    --
    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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