I have no problem shooting Polaris which is only second magnitude.
gl
--- On Thu, 1/20/11, Patrick Goold <goold@vwc.edu> wrote:
From: Patrick Goold <goold@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@pacbell.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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